>>45042280100 seems excessive to me, I would prefer a Pocket fighter system, start with your base character and as you collect power-up you will increase your attacks in level and in the case of certain pokemon, these could evolve, in this way instead of having a pokemon per slot, we would have evolutionary lines as a choice.
An example: I select squirtle, its offensive movement is water gun, after collecting power-up it changes to wartortle with the Aqua tail movement, then it evolves to Blastoise with the Hydro pump movement, and as a bonus in its special movement it changes temporarily to his mega or gigantamax form. Obviously the pokemon would have more movements and combinations, but it seems to me a simple and fun system.