Firefox doesn't come with OS and hardware to keep it around.
So they're very aggressive to introducing "app-like" APIs to Chrome even often at the expensive of user experience, performance and security.
As you said, their very goal is turning the web into ChromeOS. And the web is everywhere.
Honestly, that's NOT a good thing for the future of either the web or applications.
and their PWA partner,
https://docs.microsoft.com/en-us/microsoft-edge/progressive-...
https://blogs.windows.com/windowsexperience/2021/06/24/build...
Firefox doesn't come with OS and hardware to keep it around.