I am not in the camp that we should absolutely sell him this summer but if we got an offer of that value or better I would say go ahead and do it and bring Maffeo back. I think his success at Girona is the primary reason for so many fans willing to give up on Danilo already.
It’s not particularly about selling him, more the bigger picture of the squad and places. Maffeo is good enough and is club trained. It means we can swap Danilo for a natural left back. This means 2 full back for either side.