Manchester United is scared if they might enter relegation zone if the manager is still Amorim, but they forget that they signed Amorim because Amorim was successful with Sporting Lisbon.
Initially, Amorim was considered the most appropriate person to replace Ten Hag, so in my opinion, the management's fear of his position being closer to the relegation zone was very unreasonable because they made a very hasty decision when they appointed Amorim as the head coach, even though at that time Man United performance was improving under Van Nistelrooy.
Unai Emery is quite successful with Aston Villa, but it doesn't mean he will successful with Manchester United.
Everything is still gray, in my opinion, Unai Emery is more experienced than Amorim, he has also managed several big clubs and has recorded a good record with his previous club. He is also familiar with the EPL style of play, his success in handling Aston Villa might continue at Man United if he is appointed as Amorim's replacement, or vice versa because so far there has been no coach who has really been able to lift Man United performance.