The ISP in this diagram is literally the cable coming in to the house... I don't use their hardware. I use a UPS first, then dumb modem, then the protectli as I can create unique gateways. So for example I could run a unique gateway just for the full node and my btc only laptop that wouldn't even be connected to my Flint WiFi router.

Creating a sitiution where only my laptop on that gateway could access my node behind the firewall. Many ways to do it.

I like separate firewall for all internet coming in before it hits my distinct networks from the flint. The protectli also has a wifi network that I can use if the flint borks.