@kaa well now - having followed all the instructions including these … what SEEMS to have cleared it is
1] disconnect mouse from bluetooth
2] switch off bluetooth
3] shutdown machine and reboot
4] switch bluetooth back on
5] reconnect mouse
I had done aspects of that flow at different times - but step 3 in that order was new.
🤷🏼♂️
Who knew?
In fact - to be clear, I’m far from convinced that I know even now …
It’s just that was the last thing I did before it started working again!
ONWARDS!
(… and thank you for the response.)