The problems definitely run deeper than the coach, but a coaching change is guaranteed to improve their results.
They could double their points earned per game by simply switching to a 4-2-3-1 or a 3-5-2. Amorim is sabotaging their best players by shoehorning them into a formation that he believes in - largely because it worked in a farmers league when he clearly had the best players.
You can't tell me Fernandes should play in a two man midfield, or that Mainoo-Casameiro wouldn't immediately improve their midfield.