You are right, Inter is the most serious team to bring Lukaku they make every effort to get this player we don't know what the reason but maybe because Inter has no other choice and Lukaku is considered cheap and can be relied on. The rumors are Inter ready to release 6 players in order to secure Lukaku so we can imagine how important Lukaku for Inter even though the performance wasn't very good last season.
It's high time Romelu gets a solid future at Chelsea or he looks for a possible exits from the club. Romelu Lukaku has been an essential player for Inter Milan since his arrival, and the club is always willing to go the extra mile to keep the Belgium international. Meanwhile, Chelsea needs him to represent them at Stamford Bridge, and they are ready to support him. Inter Milan are pressing for another loan term for Lukaku, which Chelsea is willing to turn down because they have enough loan contracts for Lukaku and want him to work under the new manager, Pochettino.
Lukaku's future is indeed very complicated and I'm very sure he actually still likes playing for Inter rather than at Chelsea. But considering that his loan period with Inter has ended and Chelsea wants him to strengthen the Blues next season, it seems that Lukaku has no other choice because Chelsea has full power to control him.
On the other hand, even if Lukaku wants to leave Chelsea then he will have to wait for his contract to expire and maybe at that time Inter will still need his services but that is with the condition that even if the Inter coach is still Simone Inzaghi. Lukaku must first be patient because the current situation is out of his control and he must fully follow the path that has been made for him.