He's 19 years old. If you are saying a 19 year old has some consistency issues from time to time then that's hardly specific to his case.
The point is that United have good options in that area now, he's a box to box midfielder that can play also as a DM, a CM in general. The kids literally going to be one of the top midfielders in Europe.
Per 90 last year in the CL he actually did better than FDJ in the majority of passing metrics and also dribbling with the ball. Better in defensively metrics too (that's on the CL) in the league he wasn't at the same level for the entire season.
Would I take FDJ if Jude went to another team? Sure. Would I take FDJ over Bellingham if both were willing to join and I had to choose? No way.
United mess up this kind of signing routinely, Moyes cancelled Thiago joining from Barca in 2013, Van Gaal cancelled Toni Kroos joining from Bayern. Both very young at the top with a very high ceiling, now United have an option to pursue someone that's just a top player and will be for any team he goes to.
It's a no brainer to me, the issue is beating other teams to his signature.
Only United and Chelsea were in for FDJ last summer, the next summer there'll be 5 or 6 clubs after Bellingham and that's telling. Teams won't throw £100m into a player on a whim.