There is Dahlia OS which looks fairly promising but development takes time and it is only a small amount of people.
I like the idea of the OS being more embedded focused like Android and Chrome OS but I don’t want Chrome or Google.
Is there anything else I should look at?
I think ChomeOS is good by itself. At least it could be as a properly modified fork. The graphic shell is decent and resource-efficient. It has all things needed for using apps conveniently in VMs, e.g. crosvm, transparent proxying of wayland apps into the host system and file access with 9P. So it keeps the base system clean and secure, because all the user apps are isolated either with a browser sandbox or with a VM. I only want it would be less online-oriented, so I would like to see an offline-first fork of it, degoogled (like some Android customs), and allowing to use more then one linux app VMs.
So, I think ChromeOS is undervaluated by the FLOSS/hacker community and it has very few forks, but the majority of Linux users are focused on more traditional GNU/Linux distros and environments anyway. But with the rise of popularity of immutables, maybe it can get more attention.
Also, it is a perfect environment for PWAs.