Baam is already shitting on him in a much weaker form than the one he used against Dumas. On top of that, he's also more injured/weakened/exhausted than he was against Dumas.
Without getting carried by the contracts, Enkidu just gets sodomized very badly. Right now I don't think he would compare to a CC Tier even. Probably somewhere around the BH Tier the way I see it.
If we talk about just pure combat, dumas wins. otherwise, Enki no diffs even without using his 2nd ability. As long as dumas can't kill him, he can just possess his body and that's it. There should also be a deep meaning why headon chose enki as host for slime. Hopefully his fight with night will give us insight regarding this.
i think he is now at most top 100 tier though he looks like he gets stronger as the fight goes on i would not be surprised if he was stronger than regent at his prime.