A while ago I was also struggling to understand how constrains worked from the manual. I discovered the talk you gave at FOSDEM 2024 which made it much clearer. I want to thank you for that, Otto, and recommend it to anyone else wanting to better understand OpenNTPD.
https://archive.fosdem.org/2024/schedule/event/fosdem-2024-1856-bootstrapping-time-on-openbsd/
