That's a pretty tough hobby you've got there, OP? I'm pretty big on anime myself and if all you wanted to talk about was stuff from the 60-80s we'd probably have nothing to talk about after an hour, haha. Ever thought about branching out your interests? Music, Movies, Board Games, Books, Dancing, Yoga, Martial Arts, Arts and Crafts, Drawing, Woodwork etc?
You're pretty young still, have you tried checking out local university societies (if you even go to university)? I was able to make my entire current irl friend group from going to the vidya/anime society they had there and discovered a lot of those guys loved retro gaming and anime and I talked about it with them all the time. It's my go to for younger anons and even freshers at uni, uni soc's are some of the best places to meet like minded people.
Check out the community centers and stuff around your area too, might be a good shout if you're looking for friends.
I'd also say that comic cons can be great places to meet people, if you see someone cosplaying a character you like you can usually run up to them and just be like "woah cool cosplay" and get a conversation going, in some cases you can add their contact info and become friends with them. Meetups are good for this especially if you can cosplay a character from that, I went to an Ace Attorney meetup a few years back and joined a discord full of AA fans and while I'm not super active there anymore, it seems like it's full of like minded people that just wanna be friends and have a fun time over a shared interest.
Hope I helped you man.