If previously Chelsea could consider Aubameyang whose quality is not comparable to Ronaldo's, then I think Chelsea can also consider Ronaldo for at least 2 seasons. Short-term contract shouldn't be much of a problem for Chelsea and Ronaldo so I think he's still good for the Premier League especially for teams that need a striker.
But I don't know if Chelsea are interested in signing Ronaldo or not, but his attitude with Manchester United at the end of his contract seems to have been Chelsea's consideration before offering him a contract. So Ronaldo's current situation is really difficult, but he's still a striker worth relying on.
I don't agree with you, Aubameyang is young and he adapts very well to the new team, he already proved it in Barcelona and also when he came to Chelsea. And Ronaldo is pursued by failure, it seemed that he would be able to show his best side in the Portuguese team, but something incomprehensible happened, because he spent almost the entire match with Switzerland on the bench. Perhaps the reason was that he was unhappy that he was replaced in the match with Korea, but I did not understand his dissatisfaction, because this match did not decide anything for Portugal. I think that Ronaldo looks like a problem player now, not many will want to buy him.