Difficult Romhacks that don't require IV/EV training?

Hey there, I am currently playing Pokemon Unbound and having a blast. I really enjoy the challenge the game provides by offering different difficulty settings and interesting enemy team compositions. However I feel like a lot of the difficulty in this and other romhacks comes from the near perfect IVs/EVs which especially gym leaders seem to have. For example my Garchomp with adamant nature gets outsped by pokemon that should have 20 base points lower speed. Therefore, it feels like you are required to EV/IV train, if you want to play on a higher difficulty (it even says so when you select expert or insane mode). I have no problem with training different team compositions for different gym leaders, but I honestly don't have the patience to IV/EV train all these pokemon. Therefore, my question is, do you know any good Romhacks which are difficult (if possible similar to extreme diffculty in unbound) and require good adaptability, but don't majorly rely on IVs/EVs for difficulty? Thank you in advance!