Is everyone really convinced that Flick would not have left if it wasn't for Brazzo/the Board? I'm certainly not saying it helped and that it didn't push the situation along quicker but I genuinely feel like Flick wanted a NT job more than a club job and would have left anyways.
I am certainly not going to defend Brazzo. It has never been clear to me why he deserved the position that he's currently in. On top of that, the entire management team at Bayern has handled this entire situation incredibly poorly. (So has Flick for that matter.)
However, that does not definitively correlate to Flick staying if things were different. While obviously the media has painted this picture, that is not necessarily the case. It seems to me that the DFB job is Flick's dream job.
I don't really believe that being a club coach was his great ambition. He never really looked comfortable with it. The never ending spotlight. The constant rumors and speculation. In general, all of the side nonsense that goes with coaching a club like Bayern.
It also has to be said that some of his weaknesses as a coach started to show this season. People can say Brazzo didn't supply enough depth, but the reality is that Flick never gave several players a chance. He didn't want to rotate and so he chose not to.
Even if players like Roca and Sarr...etc, aren't up to snuff when Bayern play big CL matches, you can't tell me that they couldn't fill in from time to time in the BL.
However, that's not a problem he'll have to deal with much in the NT. He can throw his best 11 out there game after game when it matters and no one will bat an eye.
I also think his more direct and ridged style will work better with the NT. Game planning for the NT will not require as much flexibility and in game adjustments which suits him better. Just having a great plan A will be enough in most matches.
He also won't have to worry about transfers. The players that are available are the players that are available. He can plan his team exactly how he likes and only worry about injury to disrupt that plan.
With no transfer concern also comes less potential issues with management. Of course he still has people to answer to but there will be less points of contention and it will probably be less often than in his current role.
So while I can understand the disappointment with Flick leaving, I think we also have to accept that this was probably inevitable. I will always be grateful for the season he gave us in 2020. It was amazing! But instead of focusing on the negative, lets look at the positive.
2 coaches are getting what look like their dream jobs. Both appear to be very good fits for those jobs. It seems like a pretty good scenario for all parties if you can look past how some of it has gone down.
Finally, even if none of this convinces you and you're still dead set on Brazzo/the Board being the only reason Flick left, don't take it out on Nagelsmann. Give him a chance. It's in no way his fault that Flick is leaving.
Heading into next season, Bayern are certainly going to be the favorites in the BL and Pokal and among the handful of favorites in the CL as well. Bayern will play attractive football and win trophies under Nagelsmann.
Whether they win another treble, who knows but they will almost certainly be in contention to and it's really ridiculous to expect more than that given it's something that has only happened twice in club history.