Assuming that he had started from 0 dedicating himself to the mixed martial arts... to be honest there are some things like the short duration of his fighters as champions which I don't quite understand... but what do you think?
Boxing is a very good base for MMA, arguably one of the best. Even in Muay Thai you’re starting to see fighters with good boxing thrive, and in MMA it’s similar. The advantage is in favour of the boxers, if they were competent at the other fields of MMA as well!
Historically any boxer with a wrestling background would do decent. Danny Hodge, O'Neil Bell, Mike Alvarado, Kermit Cintron, Terence Crawford etc
This would all come down to whether or not the boxer can prevent take downs. If he can, he'll beat the MMA guy. If not and he gets taken down without any knowledge of wrestling to regain the upper hand, he loses. IMO, Wilder is a good example. Probably has no lower body defensive skills whatsoever, but he doesn't need them because of his monstrous punching power. Its so high that he 1-shotted Helenus and didn't even have his arm all the way extended to make his punch as strong as it could've been. Chances are the MMA guy would get 1-shotted whether Wilder catches him while still standing or being taken down. This can be said about most boxers who have strong punching power. Another thing though are guys who have a street fighting background (i.e. Canelo, Tyson). They're not going to street fight on the level of MMA guys of course, but they still know something about doing take downs and ground pounds so they wouldn't be clueless if thrown into the octagon. Between that amateur SF background + their boxing abilities, they might be able to succeed.
Kick Boxers have a better stance to take on kicks and are traditionally paid less than MMA fighters so do well in MMA once they learn some take down defense and a ground game. Harder for a boxer as the habit of just defending against punches will go against them.
