I am sure no team is interested in bringing Onana at the same price or close to what Man United initially recruited him.
Regardless of whether Onana is still in the team or not, it is only right for Amorim to bring in another goalkeeper because last season we could see that Onana did not perform well and not only that, Amorim must also get full support from the team management to build the Man United team if they want to be better next season.
When people say Onana is not performing well, I remind them that they entire team is underperforming. How do you expect a goalkeeper to be outstanding when the defense is weak. The confidence of a goalie is a good defense. Maybe a top team might not want him due to his lack of confidence and numerous costly blunders. But I am sure that an average or low-placed club can buy him. He would have to reduce his earnings and maybe sign a short term contract.
Onana might not have been in his best form since he arrived Manchester United; but one thing is sure, Onana is not a bad goalie. His move to Manchester United might not be the perfect one, assuming he moved to a somewhat stable team, he would have been at the top of his league by now.
I do not also think that another goalie would have done better than Onana in Manchester United with the epileptic form of Manchester United squad. But if Amorim wants to release Onana, it is also fine for the purpose of benefit of doubt. Onana will not find it difficult getting another club.