Depends on your expectations.
De Ligt is a player who is already on a high level and a great player in his position. As an organizer type CCB, he's in that "best of the rest" bracket with the likes of Dias and Maguire, and a few others (I picked out these two as they're the most similar to him IMO, Guéhi is another that comes to mind), below the top 2 who are in a league of their own IMO: Saliba and van Dijk. His mental profile seems to be excellent, and ten Hag will surely trust him, and all we need to do is just don't put him in situations where his weaknesses get exposed, so as a wide defender where he can absolutely get done 1v1 vs pacey forwards. At 25, he also likely has at least 6-7 years left at the top level, so if he spends those years at United, he'll be considered a fan favorite, one of the best CBs in the league, and a potential future captain as well. He'll never be THE best defender in the world, though, his profile is simply inferior to the best of the best. But definitely an elite defender that would strengthen any team on the planet.
Yoro definitely has best defender in the world potential, but he needs to be managed carefully, and even if his development goes well, and he isn't overplayed in his early years, he should only be entering those levels in his early 20s. I don't think we will, nor do I believe that we should loan him out, but the club should be looking at William Saliba when planning Yoro's development. He only became a regular starter for a Premier League club at 22 years old. Yoro playing 55-60 games per season for Manchester United in the Premier League + potentially the CL at 18/19/even 20 could do more harm than good in the long-term.
Zirkzee is a good, versatile striker most suited to being a facilitator false 9/"9.5" type for now, and he's at a good age where he is ready to play a lot of games for us from the get go. However, due to his profile/likely role in the team, I don't think elite G/A should be expected of him. I personally think he does have the tools to become more of a goalscorer, and a pure #9, but it's not a given his development will go in that direction, and if it does, it'll probably happen in his mid-to-late twenties, so a few years from now.
Mazraoui is very, very good, up there with the best full-backs in the Premier League just based on ability, but his injury record is sadly a very real concern. If we can somehow "fix" him, though, I think he'll be one of the best signings we've made in the last 11 years, especially value-wise.
Ugarte is the only (potential) signing I'm not on board with, especially for a big fee and high wages, but I'm hoping he proves me wrong if he joins. I just believe his limitations would mean he doesn't have a long-term role as a key player in our project, and spending 50m on such players is not very wise, especially if it makes it more difficult for us to obtain a long-term, elite target for this position in the future, like an Adam Wharton, for example. Don't forget that signing Casemiro for 60m basically meant we gave up on both Kane and Rice, who would've both been attainable players for us just 12 months later.
Overall, de Ligt seems to be the safest answer for your question, but it's important that we don't expect things from these players that they're not capable of. They're all very good players, but that doesn't mean they're capable of doing everything or that they're already the finished article. Realistic expectations and a lot of patience is needed IMO, especially with Yoro and Zirkzee, as I suspect the pitchforks are going to be out as soon as Yoro's rawness surfaces for the first time, and he inevitably makes a few costly mistakes, or when Zirkzee doesn't produce impressive numbers for a striker in his first few season(s).