Mid-50s here. Maybe not quite as isolated as you. Stopped working (60 hour weeks) a few years ago; family all 4+ hours away - visit 2ce/year; couple of friends on the other coast I exchange daily-ish emails, but no hang-out-and-watch-the-game people.
Everyone’s different, and I don’t really feel the emptyness you describe. I read, both print and web. I post on lemmy maybe 1/day, sometimes twice, sometimes not for days, but reading threads here, I think, satisfies my need for interaction, even if it’s just voyeuristically watching other people’s conversation. Video games, all single-player. Youtube cooking channels and a bit of my own cooking - can’t really cook that much for one person. Some wood/craft/metal projects.
I thought I’d become lonely when I stopped working. Planned to look around for volunteer opportunities, maybe take up a yoga or other fitness-type class, but that loneliness or emptyness just hasn’t hit. I did spend a couple years sort of tapering off contact with the people I used to work with: get coffee on the weekend or consult on some project, but I haven’t even heard from them in years now.
All that just to say: the people you see flourishing may just have a different experience of social satisfaction than you, and just because you see someone apparently happy in a situation doesn’t mean you can be happy in the same sitch. There’s lots of good advice in this thread, but you can start even smaller. Check in with a neighbor - make up some pretense if you need, like baked too many cookies, harvested too many tomatoes, can’t lift heavy-thing into the right place. If they aren’t complete assholes for that 5 minutes, try something else. If they are, try a different neighbor.
On the ‘in case of emergency’ thing: the last time I needed a ride to a medical thing, because they won’t discharge you to Uber, my neighbor was right there. Lived next door to him for 20 years, but we exchange, maybe, three sentences in a month. I don’t even know his daughter’s name or the grandkids that visit periodically. I don’t know what I’ll do if/when I start to have medical stuff that needs recovery assistance. Maybe a home health worker. Maybe just hope I can hold out until Medicare will pay for inpatient rehab. But I was happy to see the ‘community pulls together to help its own’ phenomenon in person, even a recluse like me.
This is one of my pet peeves with containerized services, like why would I want to run three or four instances of mariadb? I get it, from the perspective of the packagers, who want a ‘just works’ solution to distribute, but if I’m trying to run simple services on a 4 GB RPi or a 2 GB VPS, then replicating dbs makes a difference. It took a while, but I did, eventually, get those dockers configured to use a single db backend, but I feel like that completely negated the ‘easy to set up and maintain’ rationale for containers.