I'm in the same boat. I'm 21 and also tired of my generation's shenanigans.

I had a friend in high school who introduced me to tumblr and gender politics. From what I remember, she was bi and said she was gender fluid. I didn't question it too much at the time because all the words and concepts were new to me but, after about a year or two I fell into the camp of "wait, this doesn't quite make sense". We haven't spoken to each other in the past few years but, that's mostly because we lost contact. She's perhaps the only person I know, or rather knew, who subscribed to these new ideas on gender and sexuality and didn't try to push them on others.

The only lesbian I know is my ex. We ended on relatively good terms and are still friends but, it would be nice to have lesbian friends where the relationship is purely platonic.

I currently live in the UK and I thought it might be easier to make lesbian friends out here but, I don't know anymore. It's super liberal were I live that it's almost laughable (Keep in mind, where I'm from, I'd be considered a progressive/liberal/leftist; if I was in the US, I'd probably be considered a central libertarian; over here, with these extreme views to contend with, I bet I'd be called a conservative.) An example of what I mean: my mother is an artist and was invited to make a piece for a show that wanted the artists to celebrate womanhood by creating vagina artwork. My mother is an old school classical feminist so she was all for it but then someone on twitter started saying that everyone involved in the show was a TERF and got it cancelled. Things like this are what have made me (and still make me) hesitant to go out of my way to make lesbian friends because I don't know what ideological brand of lesbian it's gonna be. That is to say, I wouldn't know if they were actual lesbians or political lesbians or people jumping on the "I'm queer" train (which, from my experience, is code for "I'm a trendy straight person").

As for advice, I don't really know myself. Though, if I had to guess, I'd say the best approach is probably what you just did. Make a post and see who responds. This of course, also depends on what you're looking for i.e. potential friends in your area or pen pals. And if not here, then you could also try making posts on other forums that have like minded people.