I'm thinking something like vintage computing, Linux/BSD, makers. Not limited to those, but not things that are more fandom focused like comic con or anime. Maybe video games, if it's more indie, less corporate. No shade intended for fandoms. I've done a few comic cons and what I've learned is it's not that enjoyable for me.
I live in one of the four corners states. But it doesn't necessarily have to be in a Western US state. It's more about travel costs. Like it'd probably cost me about the same to go somewhere in the midwest as it would to Los Angeles. More expensive flight (but still fairly cheap) but lower costs for food and lodging. East coast or Mexico/Canada are probably out of the question, those flight costs are a bit too high for me to justify.
Some context: I did Vintage Computer Festival Southwest (VCFSW) last year, and I really enjoyed it. Going again this year. And I would love to find some others with similar vibes, but don't know where to look. I found a handful of different searchable convention lists and searched for VCFSW on each of them as a litmus test, which they all failed.
I met my soon to be wife on a dating app. You might think from that opening sentence that I'm about to extol the virtues of dating apps. I am not. They are garbage, so I agree the trash can is the best place.
This was during covid lockdowns, so no social opportunities, and I had recently moved to a new area and didn't know anyone nearby. So seemed the only option, terrible as it is. And yeah it worked out for me, but that's beating the odds. It was an unpleasant experience and was thrilled to be done with it. But, it might be a similar situation for others. No better option seemingly available.
That said, prior to that, I attended a lot of meetups via meetup.com and had a fair bit of luck dating through that. And regardless of if I met someone or not at any given thing, I had fun.