I don't know where you heard this because just a few days ago Olive Kahn, on behalf of Bayern, ruled out signing Ronaldo.
Free players are no longer free - this is the new reality. Look at the size of Mbappe's or Haaland's signing bonuses - previously such amounts would have been record amounts for a regular transfer, but now it's just a signing bonus.
I think if Bayern Munich is targeting this season's Champions League title, they will be interested in signing Ronaldo. However, it will cost them a lot of money. But Bayern Munich is a very rich club. They need to win titles more than money. And so I will not be surprised if Ronaldo is included in the team. But Bayern Munich will benefit even more if they can sign Mbappe. But we are not sure if Mbappe will leave PSG now.
It is obvious that you are far from football and just write nonsense. Ronaldo is now a free agent and his signing is free, but Bayern are not interested in him. Mbappe cannot move to Bayern and play in the Champions League for them as he has already started this season with PSG. According to the rules of the tournament, a player cannot play for different clubs in one season.