Thanks a lot for the feedback!
The issue with Save Preset not working in Blender 5.1.1 has now been fixed. The addon has been updated for full compatibility with the latest Blender API, and preset saving should work correctly in the new version.
If you face anything else, feel free to report it 👍
Great extension, works pretty fine with lots of options! The only problem is that the Save Preset is not working (I'm using Blender version 5.1.1).