How do you do your interior styling?

Joke aside, look into Stardew Valley and Animal Crossing : New Horizons home decor tutorials. They give you great ideas and the most important part: they don't try to shill some brand/furniture/home decor course
Also, you should put practicality over everything else, function is the most important. You need a big desk for you hobbies but it looks kinda goofy in your small room ? Not a problem it is functional.
For arranging your furniture check out Dear Modern's videos. The things he says sound kinda like spiritual stuff (idk if you are into that, it doesn't matter tbh), however the advice is solid and it will prevent you from feeling bad in your room due to the furniture arrangement.
Good luck with creating a room that will fit you !
- 2nd person recommending that channel. I know what to watch tonight.
  Didn't expect a stardew valley recommendation, but will give it a try too. Can't hurt!
  Thanks, wise Owl!
  
  You're welcome ! (I'd say that ACNH is better in this case because of the 3D)
- "guys really live in apartments like this and don't see any issue"
  Nosy people who can't mind their own damn business really judge people for things as benign as this and don't see any issue.
  (This is directed at the poster of the tweet you linked, not you.)

This looks like the humble beginnings of a sims run
- How do I open the console to type motherlode ?
  
  The console is right up the anus, but you have to tap it properly (UUDDLR) to activate it.

Have a woman do it, or end up in a man cave like me.

Your setup is absolutely diabolical, I appreciate the commitment to the bare essentials.
- Thanks for the compliment. But sadly, this picture isn't mine, I'm not at that level. I used it as a conversation starter, to get the idea across.

TV straight against the wall and a couch on the opposite wall. Matress on a bedframe and in a separate room.
- Mattress goes on the floor, dead simple really.
  Bed frames are heavy, require assembly, annoying to clean around/under. Cost more money.
  
  Bed frames provide storage space under the mattress, make it more comfortable getting in and out of bed and gives your partner something to hold onto.

Do you feel like your needs are met when you are in your space, or do you find yourself wishing there was something... perhaps a place to set or hang your keys, a table for beverages, or maybe a bedside cabinet for storing nighttime items?
Do you want something sturdier to set the tv on and hide the wires behind? Do you like the height of your bed, or would you want a bedframe with drawers or storage underneath?
Want more color or more to look at? Maybe hang a few framed photos, some artwork, posters, or even a piece of cool or interesting fabric.
Have any projects/hobbies that you might want to dedicate an area to? It could be some drawers with a tabletop work area, cabinets for storing supplies, a wall mounted folding tabletop, etc.
Are you inviting others over? Might want to have somewhere for them to sit; a couch, loveseat, recliner, etc. Ideally something you like and would want to use. It could be nice to have a side table or coffee table next to furniture seating.
Do you have/want to start a collection of anything? Small wall shelves or a little bookcase could display interesting things you feel inspired by, gifts others have given you, souvenirs, photos, etc.

Ugh. I pity people who have such a lack of self-respect that that can tolerate living in this kind of dump. If the bed was rotated ninety degrees, they could watch TV lying on their side. But I guess whoever lives here is happy to just settle for imperfection.

- as the prophecy foretold

Prioritize having it fit your needs best instead of pleasing other people who don't even live in your home. Don't fret if it might look bad to someone else as long as it looks good to you, and don't forget that functionality should come first. There's so much BS styling for the sake of styling that make homes more difficult to actually live in and use the amenities of.
Also, I find that you get used to your home to the point where any decorations fade into the background so fast that it's rarely worth it to spend a ton of effort to make it look pretty. You're not going to appreciate or even notice it just a month or two after you redecorate.

i let the wife do it. She enjoys it, I don't

The mantra of /r/malelivingspace:
proper lightsource like a standing lamp
some potted plant for color and life
get at least an armchair, dude.
TV wallmounted at an appropriate height
separation of living and sleeping (No TV in the bedroom)
get a rug that that really ties the room together
a big framed (!) artpiece like a painting or poster
There’s an IKEA couch table that used to cost 15 bucks and looks pretty good. Use rugs to create islands in the room, for example beneath the couch area. Use pillows on the couch as color accents. Maybe paint the walls something different than white.
Look on YouTube and the net, there should be plenty of inspiration.

Perfection

Bed frame. Nightstand. Plant. Painting. Then you'll be on the hot train to sex o'clock my friend.

“Single with 3 roommates at a crap job just moved in” style.

Depending on your budget, go to a furniture store (more budget) or IKEA with the intent of not buying anything but walking through and looking at everything. See what you like, what you don't. Sometimes you'll see a piece that just says "hey, I want that" and either take a picture, or note it somehow.
- Sometimes you'll see a piece that just says "hey, I want that"
  That's the difficult part :) I've never experienced that, despite having visited those stores.
  A chair is a chair is a chair, to me.
  
  A chair might be a chair, but you might find you want an end table, or a slightly more stable table with more space. I'm a substance over style kind of person, and sometimes you just need a place for stuff, bonus points if it looks good to your eyes.
  
  Take videos and pics of your room, spend 20$ on fiverr to have your room designed, buy the suggestions. Best way imho if you have 0 clue imho

I love dearmodern on YouTube and thrifted furniture

Lots of good advice for possibilities here, but let me take it a step back for you, since you most likely heard those written advice a lot already.
What you actually need to figure out is why this room mirrors your current inside. This photo tells me the person living there (assuming he did not just move in and set up a base camp to work from) has no need to go beyond basic entertainment, does not value comfort a lot and may live way more inside his head instead of the real world. With no need to expect guests, there's no need to show others his feelings, so he keeps those inside.
If that is you, you are at a starting point, not a dead end. Life is a wave. Having big Highs and big Lows is normal. Having small to no Highs and Lows is possible, but not healthy in the long run. I do understand that it feels alright having smoothness ahead, but at the same time it's so damn meaningless that even something infinitely large like death seems like just another day. Life is not about bringing a perfectly shiny well kept body to your deathbed - it's about getting there completely burned out, tires squeaking, barely alive, screaming "Wow, that was one hell of an amazing ride!" - It's the journey, not the stops that you will remember as your best moments in life.
So what you need to do first is connect to others outside your living area. No need to tell others how you live, just pretend to be interested learning other peoples ways of life to improve your own. It will naturally take a few tries/persons, but at some point it'll "just click" and you can just do your thing. If inevitably you'll receive guests, tell them you had to restart your life from scratch or something and have no idea how to live properly and ask for inspiration by those instead of some internet voices you showed a picture. Asking someone you have a connection with works completely different - do not be ashamed or something. BUT: stay open to new ideas!
It is THEN that you will receive actually good advice how to furnish your own room in a way that you enjoy. Just remember to sell on or bin things that do not spark joy or don't have value anymore. If possible, be considerate to your environment and enjoy things for what they are in the store first, but refrain from buying them if you think that joy will be gone withing a very short amount of time.
- Life is not about bringing a perfectly shiny well kept body to your deathbed - it’s about getting there completely burned out, tires squeaking, barely alive, screaming “Wow, that was one hell of an amazing ride!”
  No wonder the climate and ecosystems are collapsing.
- Hehe Waka, I know what you're talking about. I recognise it now, even if it took a few decades. It's why I'm moving :)
  The thing is, it did leave me with this, making it difficult to turn a set of objects into a living space. So I also appreciate the more practical tips :D
  Danke shön for your kindness.

I'd suggest a bed frame and unblocking any vents or outlets.
- Yes, a lot of people view the lack of a bed frame as negative. If you're dating or otherwise having folks in your room besides a single long term partner you may want to get one so people don't view it as a problem.

You should get a wall mount for the TV. Lot of people in the room? Need more space? Voila! Pushes right into the wall!
- Impressive :D Could just do that for the joke 🤔😄

If you're working on a budget like I was when starting out on my own, I recommend your first purchase to be a bed frame. You can use Ceaigslist / FB marketplace to find some really cheap used options. From there, you can start buying (used) furniture that matches the bed frame. Personally, I needed a nightstand immediately after the bed frame because I wanted to put my glasses somewhere.

https://store.metmuseum.org/home-decor
The Metropolitan Museum of Art is one of the world's best known art museums. Browse this for some ideas.
- Don't make me want to buy stuff ! 😆😭
- Wow there are a lot of gems in there. Would it make sense to pick a painting there and use it's (dominant) colors for the walls and furniture? That way there'd be some consistency.
  Is that something people do?
  
  Personally, I'd stick with white walls. Whatever else you want to do is your own affair. Glad to be of service.

So I think someone else pointed out that you need to start consciously thinking about pain points while existing in the space, and fixing those, but beyond that, d image searches, and find things you do and don't like, and then ask yourself why.
starter search terms for you: All in one living space sick gamer bedroom studio apartment ideas
as dumb as it sounds, a Pinterest board (or fedi equivalent if such a thing exists?) is actually pretty useful for this