Maybe controversily I'd definitely like to keep Mendy, I think he'll come good. We're not going to get a lot for him either way and he's started to show what he can do, when he's not injured, for some time now. Starting to get the preicison in his offensive crosses back. I don't know how but he seems to have improved defensively since we signed him, which is weird (only misstake would be at the end of the Wolves match, he had a great game apart from that one misstake).
It's not like we can get anyone better. The only standout that's not too old is Robertson, and he's probably going to retire at Liverpool.
The only two "young" that are good enough and realistic signings imo are Telles and Digne. Telles while offensively superb is unproven at this level. Digne will cost a fortune as Everton are very wealthy and they're only back up is a old and washed up Baines.