Have you heard of the news about Liverpool's possible offer for Mbappe in the near future? It is said that Liverpool will offer 300 million euros for him. I think PSG would be really willing to sell him in case there is an offer like that. Because even though PSG have to pay a lot of money to Mbappe in case of selling him early they will still be in a serious profit.
It is much better than letting him go without a transfer fee surely. In this case I assume that Liverpool wouldn't be the only team to make the same offer. Real Madrid have been monitoring his situation for a long time. I would expect them to meet the demands of PSG and Mbappe both undoubtedly.
In this case I don't think Liverpool's chance would be higher to sign him.