Seems doable - my first thought would be to use an esp c6 that supports WiFi 6 and wpa3, and im sure I've seen some people bit bang fast ethernet from a microcontroller and bridge that to the WiFi.
My main problem is that I have wpa2 iot devices that don't have Ethernet ports, so they won't connect to my ssid which has 6ghz enabled and thus is forced by my router manufacturer to be in wpa3 only mode.