It's unfortunate that using DHCP to get rough time isn't more popular, especially for devices without RTC. Sure DHCP can be spoofed and should be considered more of a last resort, but it sure would be better than nothing and ending up in this kind of a situation where nothing works anymore.

Previous discussion on similar thing: "Encrypted DNS + NTP = Deadlock" https://news.ycombinator.com/item?id=34177331