Unfortunately we have holes everywhere. It's up to the management to decide where we need fixing the most, but I think we do need at least 1 striker, 1 attacker and a midfielder as a minimum.
I'd sign Nunez and Nkunku for attacking positions. Both energetic, quick and bags of goals.
CDM we need to go all in on Tchoaumeni, but that might be tricky with competition.
As you say though in an ideal world id buy 2 new fullbacks, another CB too.
I'd like to see what he can do with the current squad though, a good coach should be able to revive some of these players. The likes Maguire/Martial/Rashford might be rejuvenated.