the deployed architecture of linux is still evolving right now and there are lots of distros experimenting with different approaches
- how the basic core OS is structured - immutability, A/B partitions, versioned rollback
- how third party applications are executed - containerization, compatibilty, virtualization, bare metal
- how software is updated and stored - package management (apt, pacman, nix, flatpak)
i'm sure i've missed other features of new linux distros. this is all really important stuff but has nothing to do with the apps you actually use day to day