Hmm...Let's see here
I think everything you mentioned is a balanced enough. The lowest would have to be Peaca cause you get Dungeon EXP which is sorta outdated, unless maybe if you have PQs, Is there even PQs for Peaca anymore? Who knows. Shadow Missions seems to be the best option for EXPs but you are limited by level, for example you can't enter an adv mission if your talent rank is too low, So far it does offer the best amount for EXP. As for commence when you start off from Level 1 you get very low EXP rates, but I heard the more you level up your commerce level the more EXP you get, I even heard that some people has gotten 50~200k EXP from 1 town runs, I would assume that would take lots of grinding to do, and don't forget about those bandits.
Why did you ask this question tho? This doesn't really have anything to do modding related