Awww I'm sorry that's been bumming you out! I'm kind of a solo player over here too, it doesn't bother me too much but this is also my first MMO. I'm used to solo play.

I definitely talk to people outside the game, but within it I tend to get a lot from even tiny interactions moment to moment. One time I needed to do a few things and saw a miqo'te girl sitting on a bench with the indication she was away from the game at the moment. My guy was in full creepypasta looking spook gear and I kind of went "huh" and sat down next to her while taking care of the offline stuff. At some point I hear a high pitched laugh and peek back up to see the miqo'te player had returned and was getting a kick out of me, so I just had my guy laugh back at her and we went on to have a tiny emote exchange. It was a small moment but made me grin a lot.

I've had really fun dungeon runs, primal fights with both duty and party finder, misadventures in Eureka, and just randomly bumping into folks. I suspect if I was more outgoing I could keep in touch more too. If socializing is a big part of gameplay for you, you can just kind of run into stuff and keep building on it I think!

Good luck!