Shadowbringers and Endwalker FATEs build your Shared FATEs ranking and are great exp. if you can group up and clear them quickly. Make a PF group if need be, people join.

I would also be selective about what roulettes you do, most don’t give any more experience than running an at-level dungeon directly. I always hit Leveling and Frontline, those are great for the time spent. The others I mainly use to get bumped up from an x0 level to the x1 level dungeon for an expansion.