I have the same problem. I've been playing for ~ 11 months, have a lot of people on my friends list BUT I've never felt this alone in a MMO. Don't get me wrong, I've met wonderful and really friendly persons, but most of time, they are new, and are so far behind that we couldn't really play together, well do current content together. I've run countless low level dungeons/trials to help them, killed way to many ARR ex primals for their ponies, just to remain alone at 70, then 80, spamming roulettes and PF.
ANd now that some are 80, they play with their RL friends OR just quit.

I'm glad to be a mentor just for the NN access though. It helps alleviating the solitude. I wish I'd be better at making friends, but I have great hopes for the incoming fellowships system. Being able to find players looking for the same things as me could be a game changer for me.

I wish you the best, hopefully you'll find a great group of friends to play with.