Yeah I agree, but also Amorim never had a chance to make transfers neither, he had the winter, but he didn't get anyone and he just sent some. So this summer should be a period where they get rid of some players, make some money and then they can use that to get some better players that would fit his system better. United had many players who just simply sucked, and only a few were a bit good, like Ugarte, Garnacho, Mainoo, and those players will of course have buyers who are interested in getting them.
We should be considering them getting rid of bad ones, but selling the good ones too. With all that money, they may do better. Erik Ten Hag was horrible on transfers, just picked bad players all around, he is a good coach, but he should leave all transfers to Leverkusen and not get anyone. Erik Ten Hag should just tell them what he needs, and they could go and get one for him.
It is tough for new manager like Amorim to make difference without control over transfers especially since he could not bring anyone in during winter. This summer is crucial for him to reshape team by getting rid of bad players to free up money and spots. Your idea of even selling good players like Ugarte and Garnacho and Mainoo to raise significant funds could work if they then buy few top quality players who fit Amorim style making team much stronger.
And Erik ten Hag poor transfer record and it makes sense that he should just tell dedicated team like one at Leverkusen what he needs letting experts handle signing right players so he can focus on coaching. It seems you believe total change in their transfer strategy is only way for United to truly get better.