I’m not a Windows guy but I note that for a thousand pounds less you could pick up a one of these: HP Desktops - HP Store UK
The tower’s more upgradable, sure - you can have a CD drive if that’s helpful to you, and at least a couple of hard drives, but if Dorico’s the only place you’re noticing problems then it might be that you don’t have a barrage of resource-hungry playback VSTs/video rendering files etc. and that you don’t need the might of Xeons. My suspicion is that there are certain actions (particularly in Setup mode) that do take longer even if you throw more processors and more money at the problem (see Dorico performance benchmarks? for some numbers).
Now sure, that little mini thing isn’t going to serve your needs if you need to run multiple displays, and you’ll end up spending some money on a USB hub (and for that matter it’s the somewhat antiquated USB2 only), but for many people this sort of machine still suffices.
Hopefully more Windows users will come to your aid soonish.