Whatever the amount any clubs buys Lukaku from Chelsea, it would still be a loss for Chelsea because nobody is going to buy him for the 100m that they got him for, not even remotely close.
Nobody is going to offer anything more that 40 million Euros for Lukaku, except clubs from the Saudi league and he has made it care that he doesn't want to go to Saudi Arabia. SO in my opinion, its best for Chelsea to just sell Lukaku at the price that Inter have offered. Chelsea do not want to keep Lukaku so what's the point of dulling the deal. Lukaku would surely be sold and if Chelsea don't sell now they might sell him for a lower price late on in the transfer window.
Well, I think that even clubs from Saudi Arabia are unlikely to risk buying Lukaku for 100 million euros

Nevertheless, the strategy of buyers from Saudi Arabia is a little different and consists in signing free agents or buying at least for several tens of millions of euros and the main emphasis is on fantastic salaries by European standards. And Lukaku wants to stay in Europe. Therefore, most likely Inter or Milan.