Without wanting to come across as a tactics hipster, I think the traditional view of formations are a little redundant. Take yesterday, we started with a 4-2-3-1, but in practice it was more of a 3-4-3/4-3-3 depending on who you want to cluster Partey with. Partey was all alone in the middle of the pitch, Ceballos was wondering around the left channel mirroring ESR on the right, Xhaka was in essence a LCB. It's only without the ball that you see the usual shape, but at that point the formation doesn't really matter.
The same thing essentially happens when Xhaka partners Partey, except that Xhaka still drops into a LCB sort of role while Tierney pushes up the left flank.
If SU and SP is the ideal template, then you need to give Partey a central midfield partner like Ceballos, but maybe someone with more athleticism and the ability to run with the ball in tighter spaces. Gonclaves looks like he'd be perfect. We'd end up with something like this on the ball:
Leno
Holding - Mari - Tierney
Partey
Hakimi - ESR ----------- Gonclaves
Saka --------------- Auba ---- Pepe