hardwired ... sod wifi
Hardwire all that stuff using POE. Wifi doorbells and camera's are useless. Simply scramble the RF
frequencies in use and it's game over...
As for wifi: separate partition , WPA2 secured , mac address restricted on router ( yeah i know that can be spoofed too) and number of simultaneous connections limited ( i only have 2 wifi devices. so if a third one tries : bingo. if one of mine no longer works : bingo. )