The only way I found to meet new people as an adult is through hobbies.
Working in tech, for me, ideally that's something that doesn't involve solving puzzles and that has an actual physical element.
I've gone through painting, Board game, Ceramics, Yoga, paintball, volunteering at the pet rescue, trampoline, walking/hiking group and other things I forgot.
You already kinda share an interest with whoever is there so it's not as artificial as some other things.
Doesn't mean everyone will be your friend, but even a hobby-specific once-a-week buddy can be a nice change.
Some of those people stick around, most don't.
I don't mean this as advice, just my experience these last few years.