Manchester United have enough money for building a good squad but they did not do well on transfer market and wasted a lot of money there while their squad quality was not improved in many seasons. First of all, improvements must come from players in the club, and next is a responsibility of head coach to do his management well in training and matches.
I believe Ruben Amorim is not a bad coach but he will face with a next very difficult season and if the club want to build up a long term development future with him, a next season target would be a position in top six. That would be an acceptable target for them by focusing on rebuilding their squad for future like 2 or 3 more seasons with Ruben Amorim.
The club owner will not spend more money to bring in players because previously they have recruited quite expensive players but the players they brought in were beyond expectations. If you look at Amorim's performance in the Premier League then he is one of the worst managers since the Ferguson Era ended because they finished just a few levels above the relegation zone, although the reason is that they focus on the Europa League but the results are also zero.
Next season there must be a major evaluation to improve the overall quality of Man United's game and a number of players must be released so they can bring in other players. The coach must also be responsible for the poor performance that has occurred because a number of players who were loaned to other clubs performed so impressively.