Now there is a dispute among the Manchester United management about why Ten Hag was not fired in the summer, because this decision was wrong and he spent 200m in the off-season, in addition they lost 15m when Ten Hag was fired and 10m in compensation to Sporting, so Ten Hag cost them a lot. I think this issue arose because Amorim will definitely demand new transfers, and maybe they already do, and the management understands that this is new expenses.
There is no need to flog a dead horse, they cannot change the past so there is need to move one. Majority of football fans and pundits expected Erik Ten Hag to be sacked after last season. But the management decided to keep him after he won the FA Cup. Maybe they thought the performance of the club would improve after the transfer spree.
Some players in Sporting Lisbon' might be willing to move with Amorim to Manchester United. But Amorim has said he doesn't have any intention to buy new players from his former team in January but he might move for some after this season. He might decide to work with the available players till the season clubs have some good players that he can maximize.