Since FATES are the only viable leveling option (unless you want to punish yourself) queues for dungeons are really long.

Some combination of following suggestions could possibly make DF a more relevant tool for leveling:

Add "queue for random dungeon" - bonus xp/currency rewards after completion. (better queue times if you let the DF decide where to put people).

Better sync scaling so xp gained in low level dungeon is actually comparable to your own level dungeon. (to encourage "queue for random dungeon").

Better xp rewards for trash/mobs/dungeon completion, so the time spent in dungeon is comparable to xp amount grinded while FATE'ing for same duration. (more people queue, therefore lower wait times).