Hansi flick have a big challenge to get through a tight schedule which is indeed starting to interfere with their performance, the number of injured players will of course test the consistency and stability of the team, so I think Hansi flick must really be able to rotate his players so as not to get bigger problems with the current tight schedule, three difficult matches with a 3-day rest schedule will obviously be the main challenge for Hansi Flick in optimizing his players, especially the opponent will they are facing is not an easy team to beat, if their can beat Sevilla, Munich and then Madrid of course that it be a prove effective from Barcelona strategy, performance, and consistency are at the moment, I think facing Munich in the Champions League is very krusial, because that will be very draining on the energy of their players before Later they will face Madrid in the El Classico match.
It will be quite difficult for Flick if the players eventually get tired because of the tight match schedule. but other teams also feel that, so the situation will be the same. the coach's ability to choose ready and right players will be needed.
Barcelona beating Sevilla at home I don't think it's difficult, they can do it. but the next match against Munich and Madrid will be very crucial. what I'm afraid of is not the players getting tired, but the ease of players getting injured when the match situation is in high tension.
I'm not sure Barcelona can get full points from the next 3 matches. but at least they might be able to get 2 wins from those 3 matches.