Well it's a fact, Bayern does need a new attacking partner, for me this has many variants, if Bayern had hired CR7 things would look different, because despite everything CR7 is an athlete, CR7 has no problem with help in the defense or cover any position besides that he can resume a game at any time, apart from that he would have been a good friend of Muller, they still have time to acquire him, Mane is very good, but if they can help with someone who is like CR7 I think that Bayern would assure there if a UCL, it would not be bad, but what the managers think is something else, and everyone has to stick to that.
Why do I feel your assumptions are related to the current situation at PSG, do we think the same?
Yes, you expect Cristiano to help Mane to complete his task up front as we see at PSG, Messi is task with help Mbappe score a goal record in every attack. You also think Cristiano will become Muller's best friend like Messi with Neymar.
It will be interesting if it comes true, because we will see the PSG trio rivalry with the Bayern trio for the UCL title.
Even this all is right, but Bayern Munich is not going to invest in Cristiano Ronaldo as this is not good investment for them, and they will prefer any young player which able to give them results for long time most chances Cristiano Ronaldo will be also not available for them in coming season as well or in winter transfer window because now things are improving in Manchester United as well, and they are improving performance which is good signal for them.
Even right now Bayern Munich is looking for attacking striker but surely their preference could be different from your all statement, and they are not luxurious club like PSG which invested big amount on stars and having results their history is completely different, and they can do much better with young players which is easy and good for them.