Vegeta mastered the ultra ego

[Alkiser]

Going back to the fight with Granolah, Vegeta was unable to defeat Granola through his doubts of regret and guilt. This set back the development of Vegeta's strength, but going further into the second half of the Granolah saga Vegeta realized with the help of Bardock's scauter footage that pride in the race is not about atoning for past sins but accepting one's nature and sticking to one's beliefs. Vegeta was no longer limited by guilt or doubt his connection to the Ultra Ego technique at this stage was already complete. I'm writing about this mainly because I keep seeing comments somewhere that Vegeta still hasn't fully mastered the technique through his doubts and guilt.

[TBMx]

Fans only think he didnt because he got destroyed even after mastering it. So they think there has to be more than this?!

No, there is no more. That's it. Evolved Ultra Ego.

[Magnificent Ponta]

Yeah, I can't say I've seen much discussion about whether or not he mastered the form/technique - just whether it made any difference to anything either way.

(Consensus is, it didn't.)

[Goku9001]

I think the next stage for both Goku and Vegeta is to make sure Ultra Instinct/Ultra Ego is a state that feels natural for them. This is what Whis conveyed to Goku from the very beginning of the arc. In that sense, I don't think either completely mastered the form. For Beerus, his mind is always on Destruction which gives him his power. Vegeta's mind isn't always on Destruction unless he gives into his instincts and takes damage directly. I'd imagine the next step is to be able to harness that power at a whim rather than having to destroy his body in the process to do so.