I do this except the offline copies are raspberry pis, they grab an update then turn their network card off and go black for about a month. Randomly they turn on the network card, pull a fresh copy and go black again. Safe from randomware and automatic.

I have a trailer (workshop) with solar power, batteries, a raspberry pi controlling everything and a cellular hot spot. It pumps all the solar, battery information and light controls over MQTT and home assistant over cellular. So yes its possible, what do you want to do?