Assuming that Amorim does persist with 343 and it's the long-term plan for the club regardless of whether the manager doesn't last 2-3 years to execute it himself, then it's clear that specialist wing backs will be the primary purchases.
When you look at who we definitely can move on, we've got the following contracts ending:
Heaton (£50k~)
Lindelof (£120k~)
Evans (£50k~)
Eriksen (£150k~)
We will probably sell Rashford, and then there's a list of players we'll be trying to shift but I wouldn't be surprised if we only manage to get rid of another couple.
I don't know who are the realistic wing back targets, but my expectation for Amorim's defence moving forward is:
RCB: Mazraoui, Yoro
CB: De Ligt, Maguire
LCB: Martinez, Shaw
RWB: New Signing, Dalot
LWB: New Signing, Malacia
Now, Mazraoui is flexible and could be used as WB in some games, but I think his main role will be as part of the back three. Shaw can do the same on the left, but he's obviously too injury prone to be a reliable part of the squad. I will just be surprised if we manage to sell him in the Summer. Dalot again has flexibility which Amorim likes, but I really don't think he's that good and should definitely be more like our John O'Shea who is generally on the bench but can play a couple of positions. Amad has also shown he can play as a WB, but I think this is something that Amorim is more likely to use sparingly and within games rather than from the start. If we need a goal, he might shift Amad to RWB and bring on a different no.10 or an extra striker etc.
MF: Ugarte, Mainoo, Casemiro, New Signing*
Pretty clear this will be our midfield unless Casemiro is sold. I'm sure we all hope the rumours of Saudi are true but I'm not holding my breath. Bruno & Mount will probably sometimes have to play deeper to cover injury/suspension, especially if we did sell Casemiro and only have two true CM's. A youth player like Collyer might be asked to step in and be a much bigger part of the squad.
AM: Bruno, Mount, Amad, Garnacho, Antony
ST: Hojlund, Zirkzee, New Signing
I'll just pool all this together as it depends who we can sell. We need to sign an attacking player but I'd say we really need to be looking at moving Antony & Zirkzee, I just can't see them ever doing anything. I think Amorim will be looking for a player who can score goals whether they're more of a no.10, wide player, or central striker more-so than a CM, unless we were to sell Casemiro on top of releasing Eriksen.
Trying to be realistic here, but given financial concerns I think we'll do very well to have the above squad for next season. I think Amorim can look at our youth squad more-so from next season as while it might sound corny, I think there are 'bad eggs' to remove from the first squad and get that culture change and mentality before you can allow youth to develop. Plus, we already have Yoro, Mainoo, Garnacho, Hojlund, and even Amad who are very young and could be swayed into some bad habits too. It'll be far from perfect, but I think that's a good enough squad to hope for next season, then work on selling another 4-5 over the following two windows.