Nope, not as a hobby but competitively against MacOS and Windows.
There are a ton of great challenges trying to compete and differentiators (by features) alone are probably not enough but key aspects I am interested in tackling are…
1. A hybrid cloud OS
2. Remote access
3. Remote data processing
There are some other ideas but I think there’s a lot of innovation that can still be done at the OS level
The use of capabilities offers a way to handle authentication without a lot of grief for accessing remote resources... the capability IS permission, so there's no need for usernames/passwords, etc.
Imagine you give a task a list of URLs (to make it simple) at startup.. that list is the ONLY set of resources it is allowed to access. No matter how confused or rogue the task gets, it can't corrupt anything else, or store trojans anywhere.