It's easy to meet people at events like disc golf leagues or board game meetups or whatever but I live in an apartment complex so I'm sure there's a few dozen people here my age that will dab and play video games and we don't have to drive 20 minutes to make that happen but how would one sus these people out should I put up posters I wish yik yak was still a thing I miss my college campus
Atomised society sucks. The only answer is just kind of do whatever incredibly awkward thing you can to say hi and/or establish contact. Posters probably isn't a bad idea.