Bayern Munich's advantage is that if/when they win Bundesliga early, that means they are going to be able to focus on UCL a lot better. Already they are very much ahead, so they could have a period where they play the young players, and bench players.
So if they do not play any of their normal good players, aside from maybe a few, they could do a fine job enough to win the league. You can take out their best eleven from them today and what remains could still win the league after this situation. Not normally, not like whole season, but they are already ahead so it should be possible for them to manage to do this now. It is not that hard and UCL is a lot more important and we could see them do a fine job one way or another if they work hard enough.
You are right that Bayern Munich's position is now very safe in the bundes league table because they have a very bearish difference from their competitors, namely Dortmund who are in second place, they will be more calm to focus on the champions league and maximize their full strength there.
This is the time for Bayern Munich to rotate their players, giving flight hours for young players and reserves, being one form of training teamwork and multiplying their mentality of playing, the current advantage is an advantage for Munich for the next season, or maybe they are still cautious? I think that there is no need to be afraid and can mix the core players with the reserve players they have so that their performance can be balanced.