Yes, it's totally advantageous for Alex. That's undeniable. However, it must be bad for Ankalaev even if he wins, because he lacks charisma with the public. And he's unlikely to be a fighter acclaimed by the general public.
Well, he would probably much prefer being an uncharismatic champ getting all the biggest names just by virtue of holding the belt, than being an uncharismatic non-champ, who would struggle to get any big money fights.
So I'm sure he won't be sad after defeating Alex.
And not everyone has to be an entertainer outside of the octagon. The most pathetic thing is fighters forcing themselves to be the next Conor McGregor or create some other artificial hype around them. I get that there's a show-business part of the mma, but it should be mostly a sport. If we forget this, we might end up with some WWE-type of drama.
What I mean is that fighters need to add charisma too, otherwise they'll earn much less. I'm sure his contract should be the same as Alex's, simply because of the value Alex brings to the fight.
So, when he has charisma, attracts fans, and is famous, he can earn much more; that's a fact. And he can also negotiate with the UFC itself. If he's happy with earning less, that's fine, it's a choice. But in the long run, that's not good, when he could be earning much more.