Great synopsis!
The cool thing about GrapheneOS: It provides basically all the comforts and usability as any Android (stock) ROM minus some compatibility issues with a portion of Google Apps and services (Google Pay doesn’t and probably will never work, for example) while providing state-of-the-art security and privacy if you choose to utilize those features. A modern Pixel with up-to-date GrapheneOS, configured the right way, is literally the most secure and private smartphone you can get today.
Windows, as any operating system, is best run in a context most useful to the user and appropriate for the user’s technical level.