Hansi Flick main focus is definitely to win the match and maintain the momentum of the team which is positive at the moment, while Revenge I think it is not the main goal of Hansi Flick remembering when Munich won big over Barcelona (8-2) he was the coach of Munich at that time, I think Hansi Flick will still aim for victory in the match while still avoiding his players from injury, Because currently Barcelona is required to be able to maintain the depth of its squad in order to remain consistent in every match they play in all competition.
Matches against strong teams like Bayern are often tighter considering the quality of the squad they have, so I think Hansi Flick should not try to aim for a big victory in the match, because it will only drain the energy of his players which will an impact on injuries.
An experienced coach aims to make his team win the match without wasting extra energy. I personally refer to Hansi Flick as an efficient and experienced coach. According to the current squad of Barcelona, the match against Bayern is very challenging. In this case a coach's match plan must be perfect and match winning plan. He will try to keep his players injury free as much as possible and keep his players ready for the next matches. I think consistency can bring more success than big wins in one match. An experienced coach often prepares his players with continuity plans.