Yes Bayern have been impressive every time they play against Barcelona even when they still have Messi. Munich has always been able to beat Barcelona every time they play. It is hard to choose which team will win this match. Both have the same points and Munich has a better goal difference. But I think Barcelona will be able to win this match.
This season could be different because the change in Barcelona's performance has also been quite visible this season and I also feel that Barcelona will definitely be able to win their home game when they host Bayern Munich in that match. However, because this is the Champions League where every team will definitely use the best quality core players, of course every victory must be achieved in a very difficult way because Bayern Munich always tries to be a very strong team in the Champions League.
As per the odds. There is no club being favored to win the game easily. This is because Barcelona is well assembled by Flick. It's different with their opponent, Munich, which is coached by an inexperienced coach. This may be the reason why there is only a slight gap in the odds owned by both teams.
And i think that will be very wise to take BTTS instead of 1x2, i meant, i believe both of the clubs will score. They will play openly in this game, and i predict we may see at least more than two goals.
I think both teams scoring is actually a sensible choice for this game.