If the new owners come in soon then Rafa Benitez

But if that isn’t happening anytime soon and they’re just looking at free agents then Quique Setién would be my pick.
Plays the same 3-4-2-1 formation as Rafa but in a more possesional and pressing style that could win over some fans.
Won at Real Madrid and Barcelona last season too so very talented manager.
Fully expecting a cheap free agent British manager on a short term contract though can’t imagine Charnley even knows who Quique Setién is.