> The way a vendor embedding NTP is _meant_ to do so is documented here: https://www.ntppool.org/en/vendors.html

Note that in the past I've had companies writing embedded linux based firmware using ntppool for time sync request their own vendor zones, however a lot of those requests were ignored so it's unclear if that's still expected. In the end they ended up just using the default ntppool domains since they never got their own vendor zones.

I remember going through the same thing. No response. This was a long time ago, though.