Hmm agreed. Understand the confusion as progressor is another term which most people have different understandings for. A progressor for me is somebody, who will move the ball forwards, connecting defense and attack. This is usually done by either passing or dribbling. Obviously no player is only a progressor or only a defensive midfielder (or attacking midfielder) but different players have different skill sets and strength profiles and while, as you say, Eriksen is pretty good at passing, he is seen as a progressor. Mount is good at passing, good at carrying, he'll suit a progressor role. Just like Bruno, who is also good at passing (if he wants to). Granted, Mount is a bit of an unknown to me, I consider him as more of an attacking midfielder, I hope he can show that he will help us moving the ball up the field.
Amrabat is great at passing. He is the main progressor for Fiorentina. Casemiro is also decent at passing but he is also great at defending, tackling, interceptions, heading, positioning. If we want a deputy for Casemiro, we should bring in somebody, who ticks the defending boxes (not to the same degree but at least to a good level and if he ticks more boxes even better). If Amrabat would do this, I wouldn't be worried at all. But there is nothing that suggests he is.That doesn't make him a bad player, but it doesn't make him a defensive midfielder.