I wonder if this is an exhibition match, and therefore to a greater extent a contractual match, then how in this case you can bet on it, because this is manipulation and insider in its purest form and relying on Pacquiao's skill here is very reckless.
I think this is just a like charity event, since it was reported that the funds raised in this event probably from broadcast rights and ticket sales will be donated to the homeless in the Philippines as well as the to Ukrainians, I don't think any sportsbook will hold this bet.
Source