yeah basciacly everyone here is kinda op. Uni has a really good move, colt knows how to hack and can use electricity to transfer to anywhere, frost... idk but I'm just going to guess she has a good ice move that always crits and is base 90 power and has 100 accuracy. Idk. point is as far as I'm concerned most of the Eevee base is op. so high bst with a good abilty would benefit.
*here's some help idk what your oc's type is but I'm assuming its the one in the image so I would make it fairy steel with flash fire and either levetate or earth eater as its hidden ability
Moonblast
Playrough
Steel beam
Tera blast (tera water for coverage for ground and fire)
and I'm not sure about what your bst would be. prob high special attack and hp with low psychical attack and speed, after all these are just guesses