Ditto here. Thought it was just me. Had lots of false fall alarms over the years, but never an alarm with a real fall. My one big fall with no injury that did require a 911 call was a very slow gentle fall. I thought because it was a gentle fall the alarm did not trip. I did however really need and used the ability to call emergency from my watch as I could not get to my phone(s).
I did not have a very good understanding of HRV until my doctor sent me to biofeedback. The technician explained that the HRV number should be above 35 and if relaxed, and/or meditating above 45. So if I quiet myself and my mind and get to a meditative state my HRV will be 50 or above. I think the hour to hour HRV values are more useful than daily/weekly/monthly averages.