I think Vegito. Typically Vegetto is a merged entity between Vegeta and Goku. In this movie specifically, either they merged the two or tricked you into thinking they did.
Vegetto is used when authors or fans are referring to an amalgamated character created by fusions between Son Goku and Vegeta, and has been canonically made via Potara Earring Fusions in the Dragon Ball Super anime series after Vegito defused due to lack of fusion time remaining. The short Fusion Dance scene at the end of Dragon Ball Z: Budokai 3 was non-canonical filler showing Teen Gohan and Krillin doing a dance before fusing as Gokhan which does not affect Vegetuh’s status as being Vegito.
Vegetto is the correct pronounciation for this character. Thus, Vegetto is the correct spelling. As “with” sounds like “wit,” which makes it a pun on words, while as “veg-” sounds like “vert-” it just doesn’t sound right. Obviously not everyone would get that though so how do you count if you can’t hear? One might say Vege-toe due to it sounding more attractive in some way or Vejuto due to the fact we have an existing word with a similar pronunciation.
Vegetto is a fusion of Goku and Vegeta, hence the name “Vegetto”. Vegito is Goku and Vegeta fused together. He’s typically referred to as Pikkoro in Japanese. Long story short, they are two different characters with similar names.
Vegetto is the power of Goku and Vegeta put together, whereas Vegito is the merging together of Goku and Vegeta into one character. They’re not always the same thing.
Vegetto is a fan-made character that was originally created using 3 of the Cartoon Network versions of Goku, Vegetta and Kakarot, and has since evolved to include other aspects from the series as well.