yeah i often cancel between content patches since i don’t have any interest in the serious raid stuff (my endgame is collecting gear for fashion reasons lol)
as for grinding while leveling, the main quest will give you enough gear, gold & exp to get one job to max level. if you play a tank or healer job you’ll get bonuses from dungeons too since they’re always in short supply in matchmaking
you have to do the main story to unlock everything and it is very much a single player final fantasy (tho more along the lines of earlier FFs, lots of talking about crystals, not much in the Sadboy Adventures department) so if that’s not your thing you’ll probably not like it? heavensward actually punches above its weight a bit more than i expected & would probably get a lot more praise if it was a stand-alone game. the writers are very disdainful of nationalism & “might makes right” and because AAA gaming is a toilet ff14’s politics are better than average.
the grinding at endgame is nowhere near as awful as destiny because the endgame currency vendor gear is actually pretty good and you can pass all but the super hardcore content gear checks with it