Even Inter are well aware of how bad Lukaku's performance was last season and because of that Inter also don't want to extend his loan period to Chelsea. Meanwhile, at Chelsea, Lukaku is no longer needed and Chelsea plans to sell him to another club. I think Lukaku's future is quite bleak and who else would a team that would sign him with the failures he always leaves the team with.
Maybe even if there is an offer from a Saudi league team later, I hope he is not too confident to ask for a higher salary than the existing offer because being able to play for a club outside Europe with an appropriate salary is very good rather than being a burden on the team in europe.
Though he is at a tough age to make that cut in his career and say that he will never play in Europe again. I think it is much easier when you are 33 or 34 and have to make that decision whereas when you are 30 you also know that you could still deliver a peak performance in an outstanding season and become an important part of a strong team. But money would heal all wounds if he ends up getting an offer from Saudi Arabia with a salary that seems to have become average these days.