Is there any chance of Garmin fixing HRV data it gets over ant+? ie. this: https://www8.garmin.com/manuals/webhelp/edge1030/EN-US/GUID-5BF2156B-9740-47F1-A564-FA22D55FDEB1.html
Seems like it records fine with BLE but not with Ant+ connected HR strap. This causes post processing the file to get Alpha 1 to be off, for example aiendurance:
https://aiendurance.com/faq
But its not a limit of ant+ as if you use a connect iq app to directly connect over ant it can give good data. For example:
http://www.muscleoxygentraining.com/2022/02/alphahrv-first-native-garmin-dfa-a1.html
I know this option goes back to the early days when the edge 305 could record HRV and those were much more cpu and memory limited. Seems garmin just reads the HRV directly from a ant+ packet and ignores how page 4 also includes the previous heart beat time which allows rebuilding missing data. (i.e. you know Heart Beat Count from ant so can see if you missed a beat so can rebuild the missed beat with the information you do know)
https://www.thisisant.com/developer/resources/downloads/#documents_tab
Maybe fix https://developer.garmin.com/connect-iq/api-docs/Toybox/Sensor/HeartRateData.html#heartBeatIntervals-var with that
Also kind of wondering, if it can't record hrv accurately from ant do the built in firstbeart algorithms use that bad data so fixing this could improve those data metrics