Fairly sure its a blanket rule across football. Any contracted player at the close of the window can not sign for another club even if released until the next window opens.
Exemption made because they couldn't have crowds. Not a chance now fans can go that restrictions will be lifted. Also broadcasters like sky would not be impressed
He was our top scorer last season. He has just come back from injury. Not sure what you don't like other than deciding he is shit from day one and not changing your mind to avoid having to admit you are wrong.