I think that Bayern Munich won't change their mind about not signing Ronaldo in the future also. They need to make a striker transfer that will be enough for at least a few years. Ronaldo is getting very old and we don't know when he will retire. His performance isn't even near his performance in his younger times. This wouldn't be a logical transfer for Bayern Munich as a result.
Harry Kane is the most ideal option for them now. However it is nearly impossible for them to make this transfer happen in the winter transfer window. Whatever amount they offer, Tottenham wouldn't like to sell him in the middle of the season unless they find a solid replacement for him. Kane also looks happy to play for them now as things are going on great for Tottenham in the EPL now.
If we look at Bayern's performances they are not too bad, even in the last 4 matches in the Bundesliga Bayern managed to make 95 shots.
But it was very disappointing that only 4 goals could be scored by Bayern, meaning that Bayern had problems on their front lines. Losing Lewandowski
had a big impact on Bayern's goal productivity. So from now on Bayern must start looking for a replacement for Lewandowski, because Sadio Mane
doesn't seem to be able to play as a center forward. Several times Nagelsmann gave Mane the opportunity to play as a center forward,
but Mane's performance was disappointing.
Actually, the strongest candidate to replace Lewandowski is Harry Kane, but as you said the chances of Bayern getting Kane are very slim.
Apart from Tottenham not being able to let Kane go this season, Kane is also not necessarily interested in leaving Tottenham at this time.
Because since Conte's arrival, Tottenham's performance seems to have improved much better. So Bayern have to look for other alternatives,
maybe I think Victor Osimhen can be an alternative if Harry Kane is hard to get. But if Bayern want to sign Osimhen they have to compete
with Man United, who reportedly want Osimhen.