By the way, Cole Palmer is a very young player and also, in fact, Cole Palmer is also a player who came from the Manchester City academy and thus,it seems no wonder Chelsea gave him a long contract until 2033. Also, considering Cole Palmer who is the main choice in the Chelsea squad, then I think it is unlikely that Chelsea will sell Cole Palmer, especially the rumor is to Manchester United. Unless, for example, Cole Palmer does not get a place in the Chelsea main squad and also, if for example Cole Palmer does not have a contribution to Chelsea, then it is likely that Chelsea will be willing to sell him.
But anyway, considering Cole Palmer who has managed to have good performance and contribution to Chelsea, and also his young age, then I sure Chelsea will keep Cole Palmer. I think there is no reason for Chelsea to sell Cole Palmer, because Cole Palmer is still very much needed at Chelsea, so keeping Cole Palmer is still very possible compared to selling him.
It is no exaggeration if Palmer becomes a new icon at Stamford Bridge, he is a young English player with great potential and Chelsea is very lucky to have him. His contribution is starting to be seen and Maresca will always give him a place. I think Chelsea will not let Palmer go for free and I think he is a valuable asset that of course will be difficult to find a replacement (a talented young player from England).