It seems personal from Southgate. There are no reports of an injury to Foden. You have to therefore assume that Foden is fit. Foden and Grealish were good from the bench against Iran. Rashford too, to be fair. Grealish had another good game when he came on against USA (Rashford less so).
You could name a number of starters who have underperformed, so you might expect there to to be a few changes for the Wales game.
My worry though, is that Southgate will continue to pick his favourites, but this mentality will not win the World Cup.
Mount has done very little in two games now. In fact, he has made plenty of mistakes. Surely, he can't continue to be a starter based on his reputation.
Trippier hasn't impressed and maybe should be replaced by Walker.
Maguire has been quite good really. He won lots of headers against USA, and without him, they would have had many more scoring opportunities. Could be carnage if he faces Mbappe though.
Rice does a job breaking up opposition play. If he moves clubs, I hope it's to Liverpool, because he seems to lack creativity.
Saka shows alarming lack of technical ability, and I've not seen him beat a man yet. He has scored though, so maybe persist.
Sterling hasn't done anything of note.
I think I would be looking to play Foden, Grealish, Rashford and / or Wilson, for Sterling, Mount, Saka. Walker for Trippier.