I need to re-read those 3 chapters so i may be getting something wrong but, i don't really see your point here. Moro's seemed to hang on against Goku and Vegeta due to his magical abilities, which Boo seems to be outright immune to (either because of the Kai's knowledge inside him being awakened or his own status as a magical being, likely both).

Against SSJ Vegeta, he won due to telekinesis which doesn't really help us to measure his power-level given that the ability can work on opponents who are far stronger (the main reason SSG Goku was weary of Zamasu's TK during Chapter 22).

His 'main feat' when Vegeta went SSG (blocking a hit from him) didn't seem to be much to write home about either; Vegeta's attitude and comments seem to suggest he wasn't really going all out, at least until Moro went serious and started using New Namek's energies and stuff.

SSB was clearly superior to him, however one could actually make the argument Moro had already been passively draining slowly before the huge planetary-drain, anyway (None of them reported a huge power-drop; however Vegeta didn't notice the loss of his energy post-draining initially, so it kinda checks out).

we're still talking about a Moro who has Goku + Vegeta + the planet's energy absorbed having his blasts deflected by a fat Buu.

We don't really know enough about Moro's draining mechanic, honestly. His constant references to the energies as "meals", implies he uses it as a fuel and burns it somehow, but that's just a guess on my part. How the energy stacks and works on his body is also a mystery too, we saw him go back to a younger version after draining base Goku and Vegeta dry after all.

Well, Chapter 47 of the manga just came out and we finally got to see Buu actually compete against modern Dragon Ball villains.

We had already seen Mr. Boo compete against a supressed Beerus way back in DBS Chapter 3. He got beat like everybody else that wasn't Rage-Boosted Vegeta.