"very long delays (If you use a micro SD card)"
I thought that writing to the SD card seamlessly was not implemented, I quote from a 2016 comment on looping:
"for longer loops this means you need to consider streaming to SDCard.
currently there is streaming playback, but no optimised writing to SDCard (afaik) , and its not trivial (though not impossible) to implement."
¿Do you know if optimised writing to the SD card has been implemented since then?