CAT 8 is ridiculous. By the time you would need CAT 8 it would probably be better to run fiber optics in the house. I’m looking to run Ethernet soon and will run either CAT 6 or CAT 6a depending on the difference in price but I could get away with CAT 5e easily for current needs I just want to be ready if I ever go to to multi-gig service.
So I just got gigabit fiber and because I didn’t have time to research and buy my own router I just let them give me the router from the ISP as for at least the first few months they’re giving me a rental credit so it’s actually free for the time being. I love that thing and of course provides good speed and all that but the Wi-Fi is impressive the house is about 2,400 Square ft one level approximately 75 ft long 20 something feet wide the router has always been in the spare bedroom / office which is off center but close to the center of the house. And the Wi-Fi signal has always had trouble reaching the master bedroom on the farthest end of the house. For years I’ve used a Wi-Fi extender and that has been fine and has worked well but it didn’t matter what router I got the Wi-Fi signal never reached where I needed to go.
The new router that my ISP provided is calix gigaspire 6.1 and they advertise it as doing 4,500 square feet. I have Wi-Fi outside a few hundred feet from the router on the far end of the house so I get halfway down the driveway before I lose my Wi-Fi signal.