i checked it - and you are right 
it does lose the sync in dependence of the player distance.
what worked (almost) for me was the following setting
“play mulitple instances” and “priority” checked on every audio component when embedded in BP actor as post earlier. There is still some minor unsync hearable but it improved the situation a lot.
In general you would need a kind of clock-device that manages the audio playback, which syncs every audio to a reliable counting clock. i never used it but i found this :
Another idea would be to look into Metasounds - although i am not sure if you can have easily different AT_settings within one metasound project.
here is an quite interesting approach for syncronized music project in meta sounds:
Vertical Re-Mixing in Unreal Engine with Metasounds + Quartz (Part 1/2) — Above Noise Studios