A lot of teams are adapting with new players to try to unite the team with a short time to get points early in the domestic league and all teams that pass to the UCL will definitely also pursue their plans to quickly get contributions from new players and create a high stability to be able to success in every UCL game. Most football fans would make Madrid a favorite to win the title again and I as a Madrid fan would say the same but a lot of things to consider.
I mean, although the arrival of Mbappe gives extra strength to the line of attack but we don't know what other teams are going to do that are currently still looking for professional players to be added to the line up. But we also have to look at Dortmund, which is now bringing Guirassy, which could be a threat to Madrid.
Even if Mbappe moved to Dortmund, it would not be a big threat for Real (at least in a two-game confrontation).
As for the next title, even if we assume that Real are significantly stronger than everyone else and are ranked as 1.3 in every match, then the probability of the title will be 1.3
4 = 2.85 = 35% This is very far from guaranteeing a title even taking into account our bold assumptions.