I'd be very surprised that a club like utd would sign a number 2 that is so young, who needs game time to develop and who isn't likely to play many games and will soon need a loan in order to play.
If you look at the majority of clubs, the backup keepers are usually in their 30s, happy to be a reserve as they've already had a decent playing career and happy to see our the last few years being deputy to the first choice. It would be the first time I can ever remember any club, let alone utd, signing two keepers in the same window. Surely this keeper was the backup choice in case Onana deal broke down.