Facebook killed Birmingham Critical Mass too, well before the pandemic.
BCM is dead?
As far as I know. I haven't gone to look for it for a while.
The problem was that a core group of regulars started a Facebook group, and after a while fell into the trap of thinking that the Facebook group *was* BCM. So one day they changed the meeting time/location, for what was undoubtedly some reasonable reason (moaning bishops, construction work, Christmas Sodding Market, whatever), with the predictable result of decimating the attendance, because most people aren't actually on Facebook.
I believe there is a kiddical mass in the heath of the king...
That seems to be doing somewhat better. I've even been on a couple of them (once completely by accident, which is surely the best way to end up on a critical mass ride).