I agree that if Mbappe does not play badly in Madrid, we realize that the player was slow to heat up in his first season.
Mbappe is a super star player but in his first season there, it is not strange to see he did not play with his best in first matches for Real Madrid. His performances are improving recently but unfortunately he got an injury that broke his flow of improvements.
In my opinion, Ancelotti will continue to prioritize Mbappe role as a center forward, over time Mbappe will be able to adapt to other attacking players, especially with Vinicius. Ancelotti is very experienced in managing star players, he will certainly find a solution to this problem. If I'm not mistaken, Ancelotti has only played a complete formation with Vinicius, Mbappe, Rodrygo and Bellingham in one lineup once. So of course we can understand if Mbappe has not fully found his best performance.
Real Madrid no longer have a super star striker after Cristiano Ronaldo and Benzema leaving their clubs recent seasons. Mbappe is not a striker but he was used at that position several times in PSG and France teams, that could help you to adapt to striker position and role and he will do it better in Real Madrid.
Because of lack of good strikers and have good attacking players at swings like Vinicius and Rodrygo, Real Madrid will use Mbappe as their main striker. Mbappe is more dangerous at swing positions but he does not support his team mates in attacking as good as Vinicius and Rodrygo. In other words, with his selfishness, the striker position is better for Mbappe individually and for Real Madrid as a team too.