The GUI could be really simple with an inner bar that is accessable with a wide arrow above the bar which you switch to change the mode of the bar.
System and tools
Active apps
Apps menu and search with programmable voice command.
All the apps on the bar bar the browser or menu scripts are wasm based offline apps.
The browser doesn't have add-ons that's done with system scripts that have strong compile-ability and can have to be coded for different machines. This would require admin privileges.
A system can be sold without admin privileges.
Also menu scripts can run on the machine.
Security is top priority and you can control linking to system extensions.
Chandler could be used for a games console device or for a tablet or for a desktop.
It should offer a platform Vulcan graphics and wasm codeing can co exist well on.
It should only have one type of file system range and should have it's own kernel plus it should follow chromium os around for compatibility not necessarily for features.
It should be able to play nicely with any common boot system.
Offline and online apps should get equal rights on the bar with icons if linked to or downloaded.
Encrypted by design.
Works well on high end and low end systems.
Total per user gui control.