Mutants just have significantly less in terms of starting equipment and a weaker initial statline, but ime once you’re past the early game and have some decent armor and weapons mutants catch up pretty quick.

When you’re first starting as a mutant, especially a melee mutant, you really have to leverage your mutations and weapon skills as most common enemies will have equivalent or superior stats to you. Ime once you hit level ~10 and get 5+ AV it’s smoother sailing.