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.
How come Aubameyang is young now?
He is 33 years old now. This is quite an old age for a centre-forward truthfully. I know that there are some examples like Benzema who is still showing very impressive performances. But these examples are limited at the same time. I don't see Aubameyang as one of those players now. He was actually like that while he was playing for Barcelona. He started to bring back his old days by scoring many goals. But after joining Chelsea it looks like he is back to where he was at Arsenal. He still has many more matches to play of course so I hope he improves his game.
Besides Chelsea wouldn't have spent a lot of money for Nkunku if they were happy with Aubameyang's performance. The Nkunku deal should be completed soon.
It is doubtful whether Chelsea will get anything better if they add Ronaldo to the team. Because Ronaldo does not have a place in the starting eleven in the national team, due to his poor form. In fact, giving a name can never survive. So the money that Chelsea will buy Ronaldo with, will benefit if they buy two or three other players.