Casemiro was almost washed at Madrid as well. He sometimes performed very bad in his last season but was essential in the big games.
You also have to question Manchester United. Something must be wrong with the mentality in the club. Any player...
Kepa started out as first choice keeper. Now Lunin has won the spot so Kepa is nr. 2 now. So that should tell you how Kepa has been doing.
He is not good enough for RM imo. I am not impressed at all.