AudioAnchor is GPL. Some features include: Additional features include: - Set bookmarks - Adjust playback speed - Export and import listening progress as SQ

AudioAnchor is GPL. Some features include: Additional features include: - Set bookmarks - Adjust playback speed - Export and import listening progress as SQL database - Sleep timer - Lock screen media controls (for Android 5.0 Lollipop and higher) Available on F-Droid. I can't vouch for it but seems to tick some of the boxes. Link: https://github.com/flackbash/AudioAnchor https://github.com/flackbash/AudioAnchor