Juventus are keen on having Lukaku after seeing Vlahovic's performance last season. Chelsea shouldn't give up on this deal as it would be a reasonable deal for them. It is obvious they can't do anything with Lukaku. Bringing Vlahovic is a chance to keep their attacking line more productive.
I don't think if Juventus even think about Lukaku, because there was some news about Dušan Vlahović leaving this team soon to other teams and we know Dušan Vlahović is an important player for Juventus but since they don't have a good financial situation even Allegri did say a no when they asked him about Vlahović, he said rejecting some offers is impossible because of their current financial situation which means we are going to see Vlahović leaving Juventus soon and play in another team in the next season.
Even though vlahovic is one of Juventus' best players and Lukaku is a good player who can still play well for the club, I don't think the departure of vlahovic is a bad thing. Juventus is in a financial bind and must sell players in order to raise cash. I think their suggestion is sound. Chelsea also wants to offload Lukaku due to a dispute between the player and the club. If Juventus decides to sign Lukaku, they won't regret it, Lukaku's performance in the serie A used to be superior to that of the premier league, and I believe that is why he preferred to stay at Inter Milan. However, due to some problems, Inter Milan decided against rehiring him.
Due to his performance in the serie A league last season, where he was one of the best players on the team and also scored goals for the team, Lukaku's bad behaviour is the only thing keeping him from joining Inter Milan. However, after he turned down an offer from Saudi Arabia and Inter Milan learned that he was in contact with Juventus about joining the team if they offered him a good amount, they viewed him as a traitor and slowed down the process of signing him from Chelsea. Since no other teams are interested in signing him this season, I believe Lukaku's best chance is to join Juventus.