I agree with you that Bayern wouldn't do much in the Champions league next season because Kompany hasn't really focused on the UCL competition last season but was more focused on lifting the Bundesliga title. The same might repeat itself next season. Liverpool looks promising because they have the squad to go far in the competition, but nobody knows if they can. Injury can also be a barrier to these strong clubs which will lead to underperformance.
Although Kompany is not really focused on the Champions League this season, Bayern Munich will still give their best for the Champions League even though they hope there is more luck for them. As for Liverpool, it is clear that they will remain strong next season, especially in competing in the Champions League even though other teams will also be quite strong like PSG and Barcelona because they will also try to be better than last season. And for the problem of injuries to key players, that is something that cannot be predicted from now on because it can happen to any team.
For next season I don't think Bayern Munich will not be serious in the UCL competition, on the contrary, after his first season Komapny managed to win the Bundesliga title again, of course next season he will focus more on the UCL competition and a team as big as Bayern Munich must still be watched out for with their targets.
I think Bayern Munich cannot be underestimated for next season, they are quite possible to make a surprise.