Same thing I've been complaining about Eric ten hag, he is full of trial and error, when I noticed this was when he had issues with Cristiano Ronaldo, Ronaldo was obviously the best attacker united had that season, he started putting him on the bench, as if he had a better plan, some times he played him towards the end of the match, a player that is capable of turning around the game in your favour. I knew he was doing that to prove a point to Ronaldo, that he is under him his control as a manager, so can do whatever he wants. David de gea was doing just fine with United, why on earth did he not renew his contract. Ten hag went and brought onana a colossal failure to team. Ten hag needs more learning, United is too big to be managed by a coach that doesn't have foresight.
We all admit that Ten Hag's first season was fantastic compared to the first seasons of coaches like Klopp or even Pep. There is no club that can suddenly be on fire and consistent, especially with a new coach, everything needs a process, for example, Man City, which has been superior in the last few seasons in the EPL since being acquired by Sheikh Mansur, has very strong financial strength but was only able to win the UCL last season.
I don't want to judge Erik Tag as a failure at this point, because there are still 30 matches left in the EPL and the journey is still very long. Regarding Ronaldo and De Gea, I think every coach must have their own set of goals for the team. We know Ronaldo is no longer young and Erik Tag needs young players, as does De Gea, he is a good goalkeeper but does not suit Erik Tag's strategy which cannot build attacks from the goalkeeper.