Add wireless access point/mesh to Sky router with per device monitoring?

[NeilF]

Your port forwarding would be done via the router as normal, nothing to do with the AP. Also you wouldn’t run a Plex server on wifi, that’s a horrible idea.

It's looking like to get any functionality of note, you can't run the mesh in AP mode, so it would need to be in "full router mode".

Plex isn't run on wifi. Just wary of gaining external access to it (from around the planet) with two routers rather than just the current one...