When you start QuakeNotch first time, macOS will ask you to give Apple Music Automation permission to QuakeNotch.

After enabling this too, restart QuakeNotch and you'll be able to use it without any issues.
If you accidentally denied the permission, you can enable it from System Preferences > Security & Privacy > Privacy > Automation > Apple Music > QuakeNotch. In this case, QuakeNotch will guide you to give the permission.
QuakeNotch has Apple Music integration and when Apple Music is frozen and not responding, QuakeNotch can freeze too.
To fix this, just quit QuakeNotch and Apple Music from the Dock or Force Quit them from Apple Menu > Force Quit.
After that, just start QuakeNotch again and it will work perfectly.
Also, if you have an app like NoTunes, please quit it too, because these apps can interfere with Apple Music and cause such issues.
Looks like yes; the app is stable enough. I'm always testing the app on different devices and macOS versions.
However, QuakeNotch is just released. If you encounter any issues, please let me know.
Yes! I'm always working on new features and improvements. If you have any suggestions, feel free to contact me.
Thank you! You can support me by buying the app and also sharing it with your friends or communities.
You can also donate me any amount on my Patreon.
If you have a tweaker app like NoTunes or similar apps that control Apple Music, please quit them while using QuakeNotch. These apps can interfere with Apple Music and cause QuakeNotch to misbehave.
If the app is started to work weirdly, just restart it. Apple Scripts and events can sometimes cause issues, so restarting the app can help. There is no a known issue but if you encounter any issues, please let me know.
If it keeps asking for permission, close QuakeNotch, open Terminal app and enter this command:
sudo tccutil reset All MeowingCat.QuakeNotch
If you have any issues or questions, please feel free to contact me on my Patreon and also on my Discord Server
You can also donate me any amount on my Patreon.