Other people already gave most of the answers, but
Parks. Go for a walk. Play a game with folks (Frisbee, soccer, whatever). Ride a bike. Read.
Meetups. I go to a tabletop RPG one. That's not unique to cities, but I can walk to this one and there are probably more people attending than you'd find in a less populous area. I also used to go to a basic neighborhood hangout one. There are many others.
The library is free. Many books and other media to enjoy.
This city has beaches. It's $3 for the subway ride there , or if I was really broke I could ride a bike.
There are free museums. I don't go that often but they're interesting.
But also
And to make it worse many of them probably have a 1 bedroom apartment so its not like you can sit in there all day long (at least i cant).
I realize im still spending money by being in my house out of town, but still, at least things I buy are owned by me, and im not paying someone else every time I want to do anything. If I want to stay at home all day I have tons of stuff to occupy my mind without going nuts.
I don't think I accept this premise. I stay home in my one bedroom without any more trouble than when I lived in the suburbs. A computer full of games doesn't need a lot of rooms. I have plenty of entertainment here. I don't see what's stifling about a one bedroom. Maybe a tiny studio I could see. But even so, when I lived in a whole house it's not like I went skipping from room to room.
88 is an unfortunate score.
Anyway. I haven't played the full release, but it's been good in early access. I think it's a little harder than the first one