He would be a excellent signing if we got him. The price is definitely a issue and could well see us making concessions in other areas of the pitch, which I believe we shouldn't do. And we should instead look to create a balanced team by bringing in players who will help us achieve that, and it looks like we're gonna require quite a few of those players to create that balance.
Rice is far superior to Mctominay and his ability to pass with both feet and position himself in defensive transitions is telling. And someone like ten Hag would definitely like Declan Rice in his team imo due to Rice being good with both feet and defensively strong.
The only concern I have about Rice is that he's playing for a coach that adopts a low/mid block approach, which means he isn't often exposed to defending large space in 1v1 situations, which will become a reality at Man Utd under a coach who looks to impose his play style on the opposition. So if we do sign him, I hope we don't pair him up with Tielemans or Neves in a compact high block, because Tielemans and Neves would get bypassed comfortably in such a setup and aren't suited to a dynamic front foot approach in defensive transitions. Someone like Caqueret from Lyon might be a better partner for him due to his moblity, industry, as well as technical ability. He's still very young but is coming into the final year of his contract and could be picked up for a very reasonable sum.