Hi @Geddy
Yes, that Apple developer link is for a very narrow and specific use case where users on your app can request the location of another user on the app via a background push notification. This is presumably what the "Find My" app uses and Apple is opening this up for other 3rd party apps to use.
Apple released iOS 15.2 beta 3 this week and so far, for me, geo-fencing seems to be much more reliable. It's not listed as a fix in the release notes aside from "bug fixes" so I can't say for certain that beta 3 fixes this, but it was a noticeable improvement over all other iOS 15 releases.
Wes