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.
Lukaku future becomes more complicated since the participation of Juventus and their offer sent to Chelsea. Previously Inter Milan came closely to have Lukaku from Chelsea but the appearance of Juventus gives Chelsea one more option and they have reasons to bargain with both Juventus and Inter Milan in order to get more money from Lukaku transfer.
The player does not show his interest to leave European leagues and he still wants to play in the Europe. It's very easily for Chelsea if Lukaku only wants money and they can knock Saudi Arabian clubs to sell Lukaku with very good transfer price.
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.
Because Juventus now want to have Lukaku, I wonder do they plan to sell Dusan Vlahovic and consider Lukaku as a replacement for Vlahovic?
But of all the things that have happened, what makes me quite surprised is that Inter have withdrawn from getting Lukaku. Even though, broadly speaking, Lukaku wants to be able to be at Inter starting next season. But indeed, as the club that officially owns Lukaku's contract, namely Chelsea, they have the right to arrange where the player wants to continue his career going forward. Maybe Juventus have a much better offer than Inter and that could be a trigger for Inter to withdraw early.
I think Lukaku has a strong mentality to stay in Europe and not be too tempted by the money that is in a Saudi league team. So Lukaku's decision to stay in Serie A is also very good for the continuation of his career if he still has a target of adding to his trophy collection later. As for replacing Vlahovic, yes, that's exactly what Juventus is targeting so they can bring in Lukaku as a replacement for Vlahovic if he leaves. Even though we know Vlahovic is much better, for standard players Lukaku is good enough.