I'm starting to confuse myself with my setup - hopefully someone can help!

I recently upgraded my speed to a 2Gb service - unfortunately my new ISP didn't advise me that my PC might not be able to use it so I've added a 2.5Gb Network Card and a TP-Link 2.5Gb switch.

The router has one 2.5Gb port and three 1Gb ports so I've currently got the 2.5Gb port linked to the TL-SG105- M2 switch with a CAT 8 cable, then from the switch a CAT 5E cable links to a Deco X20 all in my cellar (the office)

I currently have CAT 8 cables using the three free ports in the 2.5Gb switch which connect to a NAS, my main PC and a 1Gb switch which houses a second PC and printer.

I do have a ethernet cable which runs from the cellar to the living room so is it better connecting the two deco units via this cable to get the best speeds in the living room or use one of the 1Gb ports in the back of the router.

I also have a 1Gb TL-Link TL-SG105S switch in the living room which currently connects to the TV and a laptop.

So should I connect to the Mesh first in the lounge or the switch?

I hope someone understandfs what I'm asking.