Juventus becomes the best club for him next season. Lukaku have two best options for now.
1 Juventus
2 Saudi clubs
I don't see a better choice than those. I hope lukaku will able to decide it as soon as possible.
Lukaku have rejected with all interested from Saudi Clubs and seems he won't play there any more right now although has chance for few years later depend on how excited salary accepted. Last option for Lukaku between returning back to Chelsea or join with Juventus next season but need waiting done deal transfer fees with Chelsea. Its not easy for getting done deal about transfer fees after Inter Milan withdrew for signing Lukaku after second proposal with 35 million euro rejected by Chelsea.
Juventus is bigger teams and Lukaku have been adapted well with Serie A competition, its not difficult for adapting again for Lukaku if join with Inter Milan rival teams next season because regular position is most important for Lukaku than returning back to Chelsea where difficult to be main player under Pochettino.
Lukaku's future is clearly quite complicated because what he wants doesn't go his way. For him staying in Europe is the key for sure to be able to carve a few more titles and maybe after Inter pulls out he won't have a chance to go home. On the other hand, Juventus interested in signing him will certainly make his feelings quite abysmal and maybe if it's for the best then he should accept the offer from Juventus rather than lose the stage in Europe. Returning to Chelsea, of course he will not get as many playing minutes as at Inter and apart from that his experience in Serie A will certainly help the next team he will defend, in this context Juventus will seem quite happy.