I have yellowcake, and I can destroy anything with it, but it also destroys my fun.
So I have tried with other “normal” M10 legendary weapons and it was not impossible. But there was a big obstacle : ammo capacity.
In Mayhem 10, mob health/shield/armor increased by 12500%, but ammo capacity remains the same.
Hundreds of ammo cost per one mob, and after takin 3-4 mobs I should go back to buy ammo.
I know there are some skills and items that help you from ammo poverty, but that restricts build diversity.
Only when ammo capacity is increased in proportion to Mayhem level, I could play the game with my favorite but weaker weapons.