1. Good move to protect yourself as a developer and making the app easily available outside the App Store.
2. Consider supporting older macOS versions.
3. Have a look at https://workrave.org/ and https://www.dejal.com/timeout/ for additional feature consideration (competition research). (Tip: Workrave is better, even if TimeOut looks nicer - focus more on that).
Very cool idea. This would also be kind of cool to have a timer that would remind you to look at something in the distance every 5 to 10 minutes to keep your focus range exercise while using computer.
ah no, i cant actually do that, my osx is 10.6 snow leopard, would be hard to do it :) either way supporting as many versions of macos as possible is always good riddance
https://choosealicense.com/
[0] https://developer.apple.com/documentation/swiftui