So looking at what is left of the Sr squad...
GK - Ramsdale & Leno
CB - Gabi, White & Holding
LB - Tierney & Tavares
RB - Tomi & Cedric
CM - Xhaka, Partey, El Neny & Sambi
AM - MO & ESR
W - Saka, Martinelli & Pepe
ST - Laca & Eddie
That's 20 Sr players.
El Neny, Laca & Eddie are gone in July.
Leno will be sold this summer
I'd bet we try to also offload Cedric and maybe Pepe
I'd bet that Xhaka stays into next season unless Roma throws a stupid offer at us or he specifically requests to leave.
Of the Sr guys on loan, Saliba & Balogun are the most likely to be retained and I could see us loaning Balogun again for more playing time.
So for next season that would leave us with (Sr squad only)...
GK - Ramsdale
CB - Gabi, White, Holding & Saliba
LB - Tierney & Tavares
RB - Tomi
CM - Xhaka, Partey & Sambi
AM - MO & ESR
W - Saka, Martinelli & Pepe
ST - (Balogun if not loaned again)
So, if we are out of the top 5 we will at a bare minimum need...
1 GK
1 RB
1 CM
2 ST
If we have EL/CL you can probably add 1 CM, 1 W & 1 ST/W.
Now those don't all have to be starter quality but in either scenario you need a starter quality ST and in the EL/CL scenario you need that plus a starter at CM. The rest can be squad players or younger guys with potential but you are still looking at a 5-8 player summer shopping spree.