The way Bayern lost the game didn't have that much to do with the coach. You could argue that their positioning was bad and that they were extremely susceptible to deep passes, but I doubt that Kompany told his players to take positions where they are literally out of sight of the Barcelona strikers. The goals were scored too easily. Raphinha made a great move technically when he forwarded the ball with the chest, but that pass should not happen like that and if it does, the defenders of Bayern should be fast enough to be able to intervene, but they looked very slow against Raphinha. If you want to win the Champions League, you need some high speed defenders and strikers. Barcelona has both, Bayern doesn't.
The defense was somehow weak a little but I still think the game was a pure logic one, you do know that the game could be totally different if the Harry kane goal wasn't disqualified because of offside and they eventually had their 2 - 1 lead, we should have seen a total different game with that imo, at the same time both team manager have their logic way of playing... to me I think Bayern manager was aiming for last minute goal rush( with his subs) but it didn't go as planned, Barcelona looked for the perfect chances especially when the opponent team defence is relaxed & aiming for goal, that's it ! the perfect time to strike and put more pressure to win more goals... not blaming the coach for his logic but experience matters sometimes
You are talking as if offside is an unjustified part of the game and that everyone could hypothesize about the if, if only the goals were to count that are scored from offside. This makes no sense man, sorry. Offside is there for a reason and top teams integrate this as a feature up to the point where centimeters decide about right or wrong. These teams play on the edge of course, otherwise they wouldn't be Barcelona and Bayern. Therefore, offside is a real thing and Kane's goal rightfully didn't count.
Barcelona controlled the game from almost the first to the last minute. I know that to some people it didn't look like it, but in reality Barcelona was the team to decide whether Bayern wins or loses. It wasn't Bayern themselves. We all know the result and Barcelona did the same with Real Madrid. That was no coincidence. Barcelona is in impressive shape and they convert their momentum into goals. If they can keep up this combination of momentum and conversion, I think they are hard to beat. Maybe Manchester City can do it.