It is unlikely that Flick will be able to increase anything, since he refused new transfers, given the financial situation of the club. Injuries will happen in any case, and of course Real Madrid have much greater depth in the squad and the Real bench is very high quality, I think Real could make another very decent team with players on the bench. If Flick faces multiple injuries, it will most likely be an unfixable situation for Barcelona, but there is no need to think ahead, problems need to be solved as they arise. Barcelona has a good squad that can compete even with Real Madrid.
Real Madrid are no longer on the phase with Barcelona, alot have changed and watching them suffering in all angles. Hansi Flick is appointed as the new headcoach of Barcelona and we should prepare for the new management of the new coach. Barcelona have been going through alot lately with their static poor performance in La Liga and other major tournaments. The Blaugrana needs to rise back to their heels if and the only way to do that is simply making pushing efforts for improvement and signing new players.