I recently took a look at the list of training dungeons on the wiki (Good Training Locations | P.MysteryUniverse Wiki | Fandom - great resource btw for people who are looking for training spots!) and I noticed the 21-30 training levels had these options
21-30: Island Garden, Mt. Skylift, Silver/Gold Dojo, Winden Forest
My personal list has Fruity Grotto over the dojos but is otherwise very similar. However there is unfortunately a big flaw with the selection from my list. For one - 30 is the supposed target level for cliffside. For players who are just starting out and trying to do cliffside, Mt skylift and winden forest are not really options. That leaves Island Garden and Fruity Grotto which are both grass dungeons as the only “viable” training spot until these players hit cliffside. This hampers players who choose water starters heavily and mildly those who pick grass types.
In addition, all of these dungeons are kinda “out of the way” for going to cliffside. By the time players get cut they’re already exploring the north side of town since they’re coming off sourroot and that’s the “natural” direction to explore toward winden. IG is very much out of the way to the east of town while cliffside is on the west. In addition, Fruity Grotto is all the way by the crossroads where Tiny grotto is. Players going toward cliffside are likely to be more “naturally” drawn to dungeons like sourroot, sunny hillside, happiness lake, and maybe even ze aftermath over these options!
To better aid players training up to do cliffside, I think it would be a great idea to make a training spot for Pokemon in this level range similar to Fruity Grotto that can aid Water/Grass types! I think it would really help the early game out a lot and give a possible jump off spot to lead players toward Cliffside Relic through the story somehow? Please let me know what you think of this suggestion!
but more options = happy me