TCG games that aren't P2W hellscapes or are single player experiences?

If you want something really special. Try Inscryption and dont look up too much about it. It is an experience for fans of card games.

It's a shame that well-balanced TCGs are so hard to find because the booster model is much more popular, you know, because it lures gambling addicts. So these games keep going and releasing sets with inevitable power creep.

It'd be nice to find some games to play casually vs CPU or easy to play with friends. I like card games in theory but just the thought of playing with other people with thousands of hours of ranked play saps my enthusiasm.

I am playing exactly two TCGs.

One is Gwent, which is mostly competitive but with a fair ecosystem. You gain enough ressources to fastly build up a competitive deck. Since develepment will end this year you will have to learn the rules only once. you can spend money too, but you can't buy any competitive advantage with it, and players mostly do it for cosmetics.
There are single player games out there too which are sold separetely on gog.com Thronebreaker is the better one imho, while Rogue Mage tried to adapt the somewhat popular Rogue mechanics. And then there is the gwent minigame in Witcher 3 which started all this...

The other game is Skylords Reborn which is a free reimplementation of the 2006 game Battleforge. It's a Fantasy RTS with TCG mechanics. Since the developers don't have the copyright for the assets it's totally free, ressources are earned by playing, and after a while you will literally swim in BFPs. Playing is mostly PvE which can be done solo or Co-op. There is a PvP section too, but since it's player base is rahther small you may expect some waiting time for making.

if you want a tabletop experience similar to that, find a Living Card Game (LCG) that speaks to you. Generally they're designed like tcgs but you buy an entire box at a time and play that as its own contained experience, those tend to be great. Other options are finding discord servers for playing something like Magic/Pokemon over Cockatrice or Untap.in or some other virtual tabletop, that way you can get the play experience of a tcg without needing to engage with its economy at all

Lastly, I know you can probably google "games like slay the spire" and find Monster Train or Across the Obelisk and be pretty satisfied with those but in a broader sense, look into roguelike games. The gameplay loop of roguelikes i've found scratches a similar "buildcraft" itch to something like an MtG draft, and while they arent card games I get a lot of the same fun of finding and exploring synergies from games like The Binding of Isaac, Hades, Wizard of Legend, or Risk of Rain 2

I'll add another suggestion for Yu-Gi-Oh games. The only one I've played is Legacy of the Duelist: Link Evolution on Steam, and I'd recommend that. My understanding is that it has basically every card from the time it was released, so you have a lot of options for trying new things. Just make sure you get that, and not the original Legacy of the Duelist. Link Evolution has all the DLC from the original Legacy of the Duelist, plus link monsters and the VRAINS storyline, neither of which can be had for the original game.

And it's not quite a traditional TCG, but since it has heavy deckbuilding elements, I'd also recommend the Mega Man Battle Network series. Battles are more action-based than something like Pokemon or MtG, but all your special moves come from a deck of cards that you put together. Might be worth looking up some gameplay to see if it's something you may enjoy.

If you haven't played Inscryption, just ignore everything else and do that first. It's the most innovative deckbuilding game I've played, but saying more would spoil it.

Ascension is a short-ish one I've sunk a lot of hours into. It's sort of like dominion meets Magic. The expansions make it a lot more interesting, but the full package is pretty cheap. It was designed by an MTG pro player who was sick of exactly that.

Black book is excellent, and managers to put a compelling narrative spin on a TCG.

Monster train is a good "it's like slay the spire, but not slay the spire" option for when you just can't look at another shiv.

I don't play a lot of TCG, but Forced Showdown halfway counts as long as you're cool with the action side of the game. One of my favorites of all time.

Also, a lot of the Yu Gi Oh games probably count since there a lot with heavy single player content.

This is what LCGs/ECGs are for. Same thing without the random packs.

There are several old yugioh games on different consoles, more modern you’ve got games like Inscryption, Across the Obelisk, Helltrain, and just search the deckbuilder tag on steam.