If anything it makes me want routers to not even allow a blanket whitelist for all devices…
I would be fine with this. Make it as annoying as possible so people don’t blindly follow a guide to disable the firewall.
Remove firewall disable option, and only allow it to happen by DMZ or bridging to another router that would have it.
Require calling in to an ISP help desk, where they ask why you want to do that, and explain in no uncertain terms that you’re probably going to open a portal to hell or summon cthulhu. If you still want to, you have to read them out the device serial number, read out a unique code in the router admin interface, and wait a week for the option to become available.