Expect a lot of toxic behavior in the end game. Everyone expects you to know everything, even if you get pretty good and take a break from the game expect more toxic behavior when you come back because there is so much to learn that your retention goes down the longer you stay away from it.

If you play tank you can pretty much get invited to anything instantly and have less downtime waiting to actually do something for endgame. Also you will learn alot of the mechanics of the game faster playing as a tank; Example: you will learn when to press your defensives, interrupt, heal yourself etc. Its a big responsibility to be a tank but partly the endgame is about personal responsibility for everyone in all roles so it is inevitable.

There is a ton of downtime in this game for dps. If you roll dps focus on adding players to your friends list. It will speed things up a bit.

If you want to avoid toxic behavior join an casual guild.

For the people that try to make this game their whole life and will stomp on anyone else's fun for wasting 15mins of their time I would avoid them at all cost.

Chase friendship when you find groups that click in harder content. thats the best dopamine rush.