Fenix 6 playlists- where will it be stored- how can it be deleted???

Have sometimes serious Problems with copying mp3 music files to my fenix device. Either that i have to wait very Long time for copying something or i am confused when i check the Playlists on my Desktop later with them on the fenix device. Only a few of them appear on the fenix Screen, many of them not.

What is the Problem, where can i find the Playlists (m3u, wpl) on the fenix stored? searching in fenix Windows file Explorer for it brought no positive result.

I ask why i want to delete Playlists with according mp3 files from the watch but i could not find some of them. I use Garmin Express for it.

Or is it a temporary bug that Needs to be updated with on of the next updates?

Would be good if anyone could write a Feedback... Best Regards  HB