Is it possible to use a Raspberry Pi Zero+ with Wifi as the gateway instead of a 3/4? They’re significantly cheaper and it appears you don’t ever need to access the Pi itself to use the gateway.
Yes, you can use the Zero W. It will just be slower.
It works for me also with Pi Zero+.
Remember to by HDMI mini adapter if you would like to do some debugging on your monitor without ssh to the Pi.