Mbappe is an ambitious player and he will want to win maximum titles as he can, and surely both La Liga and Champions League are big titles. Winning both big titles will increase competitiveness for Mbappe to win Ballon d'Or next year. This personal award is one of targeted awards in Mbappe career and is one of main reasons he decided to leave PSG and join Real Madrid last summer transfer season.
Mbappé will do everything possible to win as many titles as possible, in fact let's make a guess, Mbappé wins everything, Liga, UCL, everything, but the Golden Ball will be given to Lamine Yamal, don't doubt that, FIFA, the corresponding entities of these awards will surely give it to him, that's how it is, now if Barcelona wins something, they will also give the Golden Ball to Yamal.
The Golden Ball was for me the first award that became corrupt, now that at least for me is an award that is not worth it.