Lots of great options for all classes, but imho, making quests PC dependent and not tying them to levels is much more fun than class dependent quests that hard lock level. I’m sure a good DM could do both, but unless the campaign is structured specifically for this kind of thing, I think it’d be more rewarding to have narrative/backstory dependent side plots/arcs for each PC rather than feeling like you need to come up with a new fetch quest so the monk can level. Not saying it can’t be done, but that way you’re not so pressed on getting them all done evenly/in order. Like if a monk learned to channel their ki at a place of great serenity and the place was being overtaken, then their ki would sense it and not be able to increase or w/e, but hardlocking them at that level until it’s fixed means that OOC the party needs to do that first so that the player can level with the party, even if in character they have more pressing concerns. It is fun, and backstory driven, but using it as a leveling mechanism can still be table dependent (like everything else imho) since that player might be feeling singled out or have issues if they are underleveled. Some tables would love that though, I’m sure.