So I'll implement an audio sync track using the 1 PPS from a GPS receptor (those pulses are precise to 10 nanoseconds typically). Between each seconds the time of day will be encoded into the track and parsed in post-production by PPSsoundmerge (a program to be written) that will merge sound clips with their corresponding video tracks (thanks to FFmpeg!) and this, before importing into your NLE.
The HH:MM:SS UTC time of day will be, for now, OOK (or ASK) modulated so maybe (just maybe) NLE softwares doing wave form analysis syncing can use it (PluralEyes, Syncaila, FCP, Kdenlive, Resolve, any other?).