It's true that Real Madrid is already 8 points ahead at the moment, but they can't be too dismissive and think they will easily win the La Liga title because there are still 10 matches left in this season which makes anything possible and even Real Madrid still has several difficult matches left. including against their rivals Barcelona.
Real Madrid will definitely be distracted by the UCL match against Manchester City, but I am quite sure that a team as big as Real Madrid will be able to prioritize both equally without leaving anyone out because both are very important to them.
The eight-point advantage that Real Madrid currently has is an advantage because currently the challenger's condition is not much better than them, so Real Madrid can be a little more comfortable leading the standings. Even though there are still several big matches left when playing El Classico, for example, Real Madrid is still quite the favorite because it is currently much stronger than several other teams.
Real Madrid are used to being under pressure when facing big matches in the Champions League and I'm not too worried about that. In fact, it will be a problem if several of their important players cannot play due to injury, making it difficult for Ancelotti to put in place the right strategy when facing Manchester City.