Air-Gap RPI-4 Ready Image
You can download a ready-made image from here:
Download Image from Here .
Please remember to change the password to your own WIFI password by editing /etc/wpa_supplicant/wpa_supplicant.conf as in the below images.
username/password: pi/raspberry
change SSID and password to your own WIFI and password by editing it on your laptop before running the ROM on the RPI.