Given that we have absolutely no depth for the front 3, that to me is the #1, priority right now. But there is no dream signing like Frenkie for midfield, that's why I see Frenkie as #1. But i do think we've already improved our midfield balance and build up play. Obviously Ten Hag alone is huge, but Martinez will be a big difference, and Eriksen as well.
Also just want to note - don't lump Fred in with McTominay as some mediocre player. He's a very good midfielder and has repeatedly showed it! Yes ideally we would sell Donny, loan out Garner, being in a partner for Fred, have Eriksen and Bruno compete and strengthen the front 3 as well. Can't all happen though, or is unlikely. At the end of the day though, it's just about having a squad that the manager feels can achieve what he wants this season. It was never going to be a 1 window rebuild. So if ten hag feels like he is happy enough with the midfielders we have if he can't get Frenkie, then so be it. Our midfield is fine to get top 4 provided we get depth in attack, as i think ten Hag will make a big difference. Frenkie is a player who I think can turn us into title challengers much quicker than anticipated, that's why ten hag is going all out for him.
I also can't understand people being unwilling to offer players a chance. They play for man united. If the manager feels they have a role to play, then they have a role to play. There are no ifs, ors, buts about it. Ten Hag is the most important man at the club right now and we need to back him and trust his judgement. He will be judged on how he manages the squad and his performances, so there shouldn't be a big outrage at his decision as long as he's doing well on the pitch for us.