why i quit before reaching endgame (feedback from a new player)

[Physic]

You have a lvl 63 RDM and a level 57 SCH and you haven't done Akh Afah Amphitheatre which is a lvl 50 MSQ quest?

you outlevel msq easily, especially if you play in smaller bursts, and do leveling dungeon roulettes. MSQ is a very poorly designed content gate. I say this in terms of how well it tracks normal player progress and playstyle. There gets to be a growing backlog of content locks. Msq is pretty good at having a plot, and providing context, but its execution is not that good.