>>17967753They are two different Mewtwo
The second one was made with research notes found after the first one destroyed the lab he was made in.
I would argue that first Mewtwo was stronger because he could manipulate the weather and actively imposed his mind control, without needing to focus to maintain it.
Second Mewtwo is faster and can Mega Evolve, sure, but if we translated it to vidya, I feel that she's around level 50 while first Mewtwo is around 80-100.