I agree with you. Dybala should stay with Mourinho. Mourinho is an excellent coach. And he is very aware of the players in his squad. He developed a friendly relationship with the players, and he knew well how to handle a player. I saw Dybala's performance with Juventus. Dybala's performances in the Roma squad have been much better than in previous seasons. With Mourinho, I believe we will see more fantastic gameplay from Dybala next season. But we are still not sure what decision Dybala will take. But I would be happy if Dybala stays with Roma, especially with Mourinho.
The renewal of a new contract with AS Roma is a sign that Dybala will stay next season, but the possibility of Inter Milan and Chelsea to sign him is still wide open. At least until the transfer window this summer officially closes, it is still possible for Dybala to move to another club. It's true that Dybala is an injury-prone striker, maybe this is the factor he refused to go to Chelsea.
Jose Mourinho has no other choice but to keep his star players from moving, because Dybala sales are not necessarily enough to buy other players at his level. The fact is that AS Roma is not a wealthy club like Man City in the EPL, which can easily buy players in the transfer market.