yep, that's right. everything you say is true that Real Madrid is currently a little comfortable even though they only have an 8 point difference with Barcelona, but even though they will lose it still won't change the position of these two teams and I think Ancelotti as Madrid coach prefers to keep physical players who can be relied on at the UCL.
In the El Clasico match, I am sure that Real Madrid will get a winning result even though they only use second tier players, because in the previous several meetings, Madrid was still able to beat Barcelona and the worst result in the El Clasico match will be a draw and I want to guess that Vinic will only will sit on the bench.
8 points is too much for Real Madrid, they will not allow anyone to get close enough to question their championship. There are still a few days before the match, this will be enough for Real to recover after the match with City, and Barcelona will also not be in the best condition after the defeat to PSG. And besides, the match will take place in Madrid, so I don’t think that Barcelona has a chance to win this match.
Barcelona is still in shock of what PSG did to them, and they might not be able to put themselves together to bring out the best in them. Real Madrid will be motivated the more in this match, because they will not want Barcelona to make them drop point. Their frontline is strong compare to Barcelona.
I know that Barcelona have picked form, and they might also want to let Madrid to know that they can win the game, if only they can outsmart Real Madrid strategy and take it as an advantage to win the match. I don't think that even if Barcelona play the best they can, that they will win the match, the highest that they can do is to draw the match and share points. Madrid is still the favorite to win because the match is taking place in their home.