We haven't talked much about
Router Placement yet. Yours is on the middle floor, likely a good thing. You don't say but often, too often, the router winds up in a remote corner of the house. I've had a couple of sites where I was considering adding an AP, Extender or "Mesh" but, on a whim, grabbed a few feet of Ethernet cable and simply relocated the router up off the floor and a few feet more towards the center.
Oh, and before I forget, many on this forum are also Netgear fans. I don't keep up myself but the R7800 rings a bell?