But but Enma
There are so many threads on this basic topic that I've lost track.
Is Enma additional or is it a replacement to compensate for something missing? Yes.
Is it stronger than what it replaces? Shusui was a black sword so no.
Could Zoro become as strong if Enma didn't exist? Yes.
If he loses Enma does he become weaker? No.
Enma is not a power up.