Kompany is new to the business but that doesn't mean he can't be up to the level of coaches like Pep Guardiola, Ancelotti or even Mourinho, he has made some mistakes but he's still on track to me. And for Kompany to last long as the manager of Bayern Munich I think winning the champions league will give him full ground at Bayern. For some coaches that started with with him like Lampard and Rooney (as ex footballers) I think Kompany is the best among them all, he just need to give the club something they have lost and that's the glory of Bundesliga, getting them that trophy is going to be a big win for him and I don't see the management sacking him.
Mistakes can happen to anyone, the most important thing is how they deal with them. So far, nothing bad has happened to Kompany, compared to Guardiola, who you mentioned, he had a few failures in the Champions League, but they will definitely get out of the group and they are doing well in the Bundesliga too. It is important for Kompany to win the Bundesliga, this is a title that will be important for the team, to get it back after an unsuccessful season, and if they manage to play well in the Champions League, then this will be a pleasant addition.