I don't know if it will help any of you, but the issue went away, when I
individually removed all devices in Home from groups I'd created, then
deleted the groups. It would then let me add the Voice Match for my kids
accounts and I could re-create my...
I too have the same issue(trying to add voice recognition for my
daughter's on a new Nest Hub device in their room). Rolling back the
version of Google or Family Link hasn't helped. Very frustrating!
