It's tough, and I must admit the times I've lived on my own for any length of time weren't always easy. I've done it twice.

First time I realised I was spiralling a bit and looked for a form of exercise I enjoyed, which was cycling, and getting into that, doing long-ish rides every so often, it really helped my outlook, I got a little fitter and it made me feel more positive. There are also cycling groups in most places that you can join, that make it more of a social activity, some more relaxed than others. It doesn't need to be cycling, but some sort of stimulating activity is always good, even better if it can casually involve other people.

Second time, I just spiralled into drinking too much, too often, and it wasn't healthy. So, you know, I'm only so good at following my own advice.

You've already identified the cliches - 'get a hobby' being a big one, but the thing is they are clichess for a reason. If you can find something that interest you outside of the house, you'll probably naturally meet people while doing it, get some interaction and improve your mood.

You could look into volunteering things that are going on in your local community. My local community does a 'planting day' each year where volunteers plant shrubs and trees in an area undergoing regeneration. There's some light socialising, you're doing something useful, it's good for you. They do various other volunteer days throughout the year, and they aren't a big, regular commitment that way.

I love games too, but IMHO they're really good as respite from other things, not as a replacement for social interactions.