I always quite enjoyed being able to find the pokémons that I should expect from certain environments (insects in forests, etc..) but Dreepy's spawn location really doesn't seem to match the pokédex entries from the main games :
-Pokémon Sword
After being reborn as a ghost Pokémon, Dreepy wanders the areas it used to inhabit back when it was alive in prehistoric seas.
-Pokémon Scarlet
In the evening, groups of Dreepy will fly at high speeds over the ocean and poke at Pokémon in the water for fun.
-Pokémon Violet
It has a habit of biting at Clauncher even though it doesn't feed on them. This is said to be vestigial behavior from when Dreepy was alive.
I understand that this is far from being a priority, but currently it is set to spawn only in Savannas and Evil biomes which seems a bit unexpected for me.
As always, thanks to every member of the staff for this great mod.