Contrary to popular belief, elite boxers would be extremely dangerous in an MMA cage.
It's not out of the realm of possibility, it just comes down to how committed the individual boxer is. These top boxers can afford 3-5 million dollar camps easily, it's not the same.
Folks act like it takes a lifetime of training to get legitimate TDD and a half decent guard in BJJ, if an elite boxer is serious, he will be able to compete.
The conversation always comes down to can they survive low kicks and the grappling? If you can be decent at defending both you will be a championship contender. Elite and semi-elite kickboxers already have the low kicks on lock, so they come right over and dominate in MMA.
We literally saw former NFL player Greg Hardy come into MMA late as all hell with zero background, and he took Volkov to a decision and did pretty decent. The only thing stopping us from seeing the truth is that the pay in MMA is just not high enough for anyone to take a crossover seriously, they would have to be washouts from their respective sport.
For decades it's been said that a strong grappling base is the key to having a successful MMA career, but times are changing. Now we are seeing fighters build their game off of their striking, because you don't need to be a wizard on the ground, you just have to know how to stall rounds and mitigate damage. How many of the UFC champions right now even employ offensive takedowns? MMA rules are designed to favor strikers, it's why every round starts on the feet, and why fighters with a grinding style are penalized for "inactivity". I don't understand how folks can see Greg Hardy do half decent, and you don't think one of the greatest punchers on the planet with unlimited resources couldn't hold his own with the proper training and experience.
I'm not even saying Joshua could beat Ngannou in MMA, but the dismissal of true world class athletes is crazy to me. Boxing is a much harder sport than MMA, the guys at the top have incredible skill and talent. In MMA you can become a champ while having extreme deficiencies in your game, it doesn't work like that in other high level martial arts.