So I'm not sure about the PrjM/Classic Pack
directory, since my phone doesn't have that folder, but I did recreate the situation with the /android/data/com.psperl.projectM/files/presets_dir
. I pulled the APK for ProjectM Pro from my phone and opened it up, and confirmed that the presets in that folder are part of the apk. It appears just removing them from the filesystem won't do anything, as you found, they'll just be replaced when you relaunch the app.
I was able to go into the app, open the "All Presets" playlist, and remove presets, and that seemed to be permanent, even though the files still existed in the filesystem. I'm not sure this is working as intended. I wouldn't think you should be able to remove presets from the "All Presets" playlist...
The solution you probably need is to set up customized playlists, but I just found this comment response to a review on the free version's play store page:
> Sperl Heavy Industries September 5, 2020
> The playlist stuff is broken. I'm sorry. I need to rebuild all of it.
Looks like we're waiting for a fix. :-/