I think ENma is all of these things that people claim it to be, just a little bit less extreme
1. A powerup: well yeah, it makes Zoro's attacks more potent by drawing more of Zoro's haki in comparision to say Shusui, but it's not that kind of powerup that instantly makes Zoro jump tier. Zoro has to EARN that powerup. It's not a free upgrade by any means. ZOro has to trade Shusui, Zoro has to TRAIN to master Enma.
2. A training wheel: it helps Zoro master his
charka haki control, by Zoro's own word.
3. A magic sword: it does grant Zoro the ability to suck more of his haki to create bigger strike, it's not that kind of magic sword that's gonna flung from Zoro's hands and 1 shot everyone. It's a curse sword that has a mind of his own, but that doesn't make it any more special that say Kitetsu Swords. It could very well contain a piece of Oden's soul in it, but that doesn't make ZOro's feats with Enma any less impressive. The sword up till this point has always been using Zoro's haki for all we know. Kaidou sensed Oden's "prescense", not his haki. Sword containing past owners' spirit is not new, when we have Kawamatsu explaining it literally 50 chapters ago.
So, don't expect Zoro to just throw away and destroy Enma like Sanji did with the raidsuit. It's Zoro's Wano Arc's powerup, same with Sanji's Exoskeleton.
Oden's prescene is still lingering on Enma, and in Asian's culture, a spirit still lingers on because it still has unfinished business. So when that bussiness is finally completed, maybe Oden's presence will finally rest in peace and no longer haunts Enma (and us readers)