This thread had gotten pretty deep in the weeds with detailed discussions on two different topics: using a V2 with a thread border router and using the “give devices to someone else“ in order to create a subset of devices that could be left behind on a V2 hub When migrating to a V3.
because the conversation was getting really difficult to follow in the context of the original question, I have split those posts off into their own threads.
For anyone who would like to see those details here are the new links