Okay.
So temporarily I'm running with an
Asus GT-AX11000 connected directly to my ONT.
This provides 802.11ac 2.4 GHz connectivity and 802.11ac/ax 5 GHz connectivity to the property.
It also connects via a dedicated 160 MHz 802.11ax bridge to the same type of device in the office.
That device goes via 2.5 Gbit Ethernet to a Mikrotik CRS305-1G-4S-IN switch.
Longer term I'm looking at getting 10 Gigabit Ethernet between Ubiquiti UDM Pro and another CRS305-1G-4S-IN which will then feed one of the GT-AX11000s via 2.5 Gbit Ethernet and then the office CRS305 via ultra-fine fibre, again at 10 Gbit.
Acquiring the fibre isn't the easiest thing but is a work in progress. The AX11000s can then do wireless AP downstairs and mesh AP upstairs duty