@DAOWAce: As a guy who plays a female Au Ra I think it's a bit ridiculous to say "notably for e-sex". I find the concept itself ridiculous, and I've never been approached for that reason nor have I ever heard from fellow players and guild members about that being an actual thing. I remember back when Tera was big there would be a couple trolls in main channels trying to charge for "cybering" but I've never heard of a legitimate e-sex activity.
Most of us simply play women because if you're gonna be staring at your character constantly for the years you play then you may as well make it pleasing to the eye no? A large part of MMOs is the gear grind so if you're essentially playing dress-up all the time you should like what you're looking at. That's also why, as you mentioned, gay guys and girls often play as male characters.

@siarhei: What Deltath said is true. The story in FFXIV is absolutely amazing. It's by far the best story ever featured in an MMO and I've played dozens of them. The world itself is also massive and stunningly beautiful. There's so much to do in-game that you will never get bored. You can level all jobs, combat, crafting, gathering, on one character so there's no need to create new ones if you decide you don't like the job you're playing.
It does have matchmaking of course, if you're referring to dungeons and raids and stuff, just as most all MMOs do. You can also always join a guild if you want to have people who will help you progress. The only issue with the game is that very low level combat can be rather boring, as you only have a couple skills to spam while your character auto-attacks, but this goes for most MMOs and as you progress you'll get access to many, many more skills that eventually create very complex endgame rotations for the different classes.
If you don't like playing by yourself you could always look for a guild as I already mentioned or use an FFXIV discord server (there are many) to find a friend to play with. It's an amazing game, you should definitely give it a try.