So, this isn't the first time someone suggests something like this and I know very well that Wynd doesn't support the idea of locking devil fruits moves and prefers getting all of them once you eat the fruit, but please give this one a chance and read first before disregarding it.
Currently in the mod, there are some devil fruits that just turn you into a god once you eat them and are, at least IMO, very boring to both use AND fight against in a server because they are just way too OP right off the bat. I'm not saying fruits shouldn't be stronger than not having one, but there are some moves that I think would be better if they were locked behind a certain requirement, or at least make their strength and effectiveness scale with doriki.
Let's take, for example, the Gura Gura No Mi. A very strong and destructive fruit. But why should a new player with 15 doriki be able to completely destroy a Marine Captain, along with an entire marine base, despite being really weak? I know that's the point of the devil fruit, but let's be for real, if a random civilian got that fruit, they wouldn't be able to accomplish such things in the One Piece universe. Instead, what if the range, destruction and damage scaled with the player's doriki? All of the fruit's moves are intuitive and not complicated, so theres no logical reason to not have them right off the bat, but at least you'd have to actually work a little before being able to do what Whitebeard does in the anime.
Other fruits with less intuitive moves, like Gomu Gomu No Mi's Gears, would perhaps require repeated uses of the abilities in order to obtain such things. (Again, having a player with 200 doriki being able to go Gear 2nd doesn't make sense logically, they should at least have tons of experience with their fruit like Luffy does in the anime).
Other fruits, like Logias, should still turn you into a god from the moment you eat them, since the logia invulnerability isn't something the users have to train or work for, and is instead a passive ability of their fruits.
IMO, this not only helps with balance (since you actually need to be strong in order to use a fruit's full power), it would also make more sense and follow the source material (which I know is a thing this mod tries to accomplish).
TL;DR: Give fruits more damage/range/destruction/effectiveness/etc scaling with doriki and lock certain unintuitive moves behind either a doriki wall, a quest, an amount of moves used or whatever else you come up with (could even vary depending on the move).
And yes, this should be a config option since I know some may not like it as much as others will.