Rice can play well as an 8 too. And he has the benefit of being backup for Casemiro at the 6 if he gets injured or when he inevitably gets suspended.
Our goalscoring issues have been from a lack of a consistently fit CF who can actually put away chances.
Rice can play as an 8 in the same way Casemiro can play as an 8. They are both defensive midfielders and should be played as such. I don't know why this obsession with a defensive style have convinced so many fans is the way forward. There is a reason not one of the top teams play with two defensive midfielders. The only team I can think of that comes close is Bayern München, but Kimmich is also a playmaker for them.
I'm not saying we absolutely need to sign Mount, or that there aren't any other ways of playing, but neither Rice nor Casemiro are players that dictate tempo. Their main job is to shield the defence and break up play. Why do we need two midfielders whose primary function is to break up play when we're the team that is meant to dominate the game? Not only does it not make sense, it goes against what Ten Hag is trying to build here, so from a fan point of view, there is no point of even hoping, because the only likely reason we would buy him is if Casemiro turns to absolute shit, or if he moves to another club.
Personally, I'd prefer if we got Rice last summer before Casemiro. Not because I think he is better, but because of his age and how long he could realistically play for us. Defensive midfielders of high quality don't come around too often, so when they do, they should be snapped up quickly before another club does it. Now, we'll have to look at replacing Casemiro in maybe two summers. We should definitely get a back-up though, but Rice won't come here to sit on the bench, and our budget wouldn't allow us anyway considering how many positions we need to fill.