Ronaldo is old now but his age has not affected his performance on the pitch, all the clubs wanting to sign him believes that he will still prove that he is still a good player that is why they keep pushing for the deals to bring him their various clubs. So far Ronaldo has been linked with a move to Chelsea, Bayern Munich, and PSG. I believe they know his worth that's why they aren't considering his age.
No doubt Ronaldo performed very well last season despite Manchester United's poor outing, he was their best player of the season and also the club top scorer so moving to new club he will also perform well and the club's finance will be increased too as as result of his signing.
I think Bayern will be interesting to recruit Ronaldo if Lewandowski goes to Barcelona, but he is still on Allianz right now and the rumors, Barcelona can't reach a contract agreement with Bayern. So, I believe Ronaldo will not go on to Bayern for this session even though MU didn't play in the Champions League. Maybe if any other reason like incompatibility with Ten Hag style, Ronaldo will leave in half session in winter transfer I guess.