Before El Clasico match, both teams have busy schedule match after international break have one La Liga match and few days later will play in UEFA Champion League match. I think both manager between Hansi Flick and Carlo Ancelotti will make huge rotation for facing most important match because high intention both teams most important winning on El Clasico match than other match.
Currently Barcelona is ranked 1st and Real Madrid is ranked 2nd in the standings. Both teams are in their best form and this makes me really looking forward to this season's el classico. They have a busy schedule and this will determine which coach can rotate players well before the el classico match. Real Madrid wants to get 1st place and Barcelona wants to increase the points difference from Madrid. This derby will be an important match for both teams so I think this game will be very exciting to watch.
Barcelona remember have been the better team than Real Madrid this season especially in the Spanish La Liga so I think they have a slight advantage that comes with maintaining a good form. Both teams like you rightly said will have a busy schedule before the encounter at Santiago Bernabeu on 26th of this month which is still over two weeks from now.
As a Real Madrid fan and one who's been seeing the performances of both teams since the start of the season, I think Barcelona is more favored to win the game but since Real Madrid will be the home team, I'm very optimistic that Carlo Ancelotti's men will get all three points