Ronaldo has already said he will stay at United even if they fail to qualify for the Champions League. United is more than just another club for him, so I don't think he will change his mind. Given his age, there is a possibility that we will not see Ronaldo in the Champions League anymore, but I agree with his decision. Let him finish his "big" career at United, and in retirement it will be possible to play in America or somewhere else.
There were several rumours regarding Ronaldo future in Man Utd and some people said he possibly will stay but some of them too give the opinion he will leave Man Utd after this season ended but Man Utd will under new manager Erik Ten Hag next season and his future also will be determined in the next few weeks but the rumour is Erik Ten hag want Man Utd filled by mostly young players so if this rumour true then possibly Ronaldo will be excluded his long term plan and the situation will change that he might be will leave Man Utd this summer
I remember these rumors, it concerned the opinion of the club's management, but as I understand it, there was no unity on this issue (and it is generally unknown whether these rumors had any basis or not). With the advent of Eric Ten Hag, of course, the balance of opinions will change, but I don’t think that he is so radical as to come and say: “we fire all the old ones, leaving only the young ones.” In addition, Ronaldo, whatever one may say, is in third place in the list of league scorers and is close to the first, so it is hardly possible to make any claims against him - he does his job.