There is no doubt that Mbappe is a talented player. Mbappe has the ability to score a lot of goals. We haven't seen Mbappe play well in the first three games of the season. However, Mbappe managed to score two goals in the fourth match. Madrid won 2-0 against Real Betis and Mbappe scored both goals. Mbappe is slowly adapting himself to the Madrid players.
Mbappe shown his great talent since he was very young as a teenager in Monaco, and continued to show his world class ability in PSG through many years and more than that with his national team in many big tournaments. The transfer to Real Madrid is a first step to achieve his dream that includes many targets, playing for his favorite club Real Madrid, getting chances to win big titles. He is in a right place already but there are many challenge for him to go through and win titles. He needs to work friendly with the coach and his team mates, and should not show his high ego and disrespect his team mates as it is not good for his career in Real Madrid.
I do not think that there are that many things left to win, maybe just UCL obviously, but he can win that with Real Madrid easily, many players at real wins it easily, so it wouldn't be really a big deal. Even if they end up winning it a few years later and not this season then it would still be possible and they will still win it, there is nothing to worry about, they all know how to win it and won it before so they will get one with Mbappe as well. I think it's clear that Mbappe doesn't really have to do that much to win something with this team.
Sure he went there to chase his dreams and goals, but the goals with Real Madrid is quite simple, it is not really anything to be happy about, when you win half of the all UCL's in the last decade, when you win it, it's not really a big deal. The bigger deal would be if they end up losing, because they should be a lot better than that, and shouldn't be losing and if they end up losing then it would be quite funny to see that and I think it would be humiliating for them too.