It is very reasonable if Morata rejected the offer made by Al Qadsiah. Morata still can play well in European leagues, he doesn't need to more to SPL. Moreover, it seems difficult to win SPL trophy if he joins Al Qadsiah. I think Morata may consider the offer it it is made by Al Hilal or Al Nassr. Sure, Morata wants to play with the team which is possible to win a trophy. Morata doesn't want to join a club because of the high salary only.
Well, AC Milan looks a good destination for Morata. He will be the main striker in AC Milan, AC Milan has no strong striker after Giroud left the club. I think Morata is possible to move to AC Milan as long as AC Milan wants to pay the transfer fees. It won't be expensive because Morata market value is only around €16m - €20m.
Having prediction about his carer is currently too early as things are going most chances he will be started thinking about his future after having final of Euro 2024 against England which is going to play on 14th July in Germany but as things are going most chances his career at the Atlético Madrid is already ended, and now he is looking for the new destination where he will do things for the future, and currently we are having two good options for him with first is AC Milan and second is Al Qadsiah which is newly promoted club here and looking for strong squad which give them good start and secure their future.
No doubt every player wants to play for the winning team with this now most chances if he is going AC Milan it is not surprised but if he has luxury offer from the Al Qadsiah this could be also considerable because as we have development in Saudi League teams are doing good work and having better things for their future, so this transfer is also looking possible.