It's always a shame reading about a veteran player leaving the game, but it sounds like this is what's best for you. I also find PVM content quite tricky, and have accepted I'll never be great at it, but I have gotten better with more practice.
Maybe after a few weeks you'll come back and have another crack at it, and you'll realise you are capable
Completely agree, I don't want to spend my life tick perfect clicking a bunch of new bosses with limited reward. New updates are geared towards a minority of players who like to play like that and the game has become steadily more and more unenjoyable for an average player. I have also cancelled membership.