Apart from being open source what is Linux? Could I not create my own operating system that is different to windows or Macos and call it Steve, again there might be an awnser for this and sounds stupid but its more out of curiosity.
I’m pretty sure Solus is a Linux based OS, at least according to Wikipedia:
Solus (previously known as Evolve OS) is an independently developed operating system for the x86-64 architecture based on the Linux kernel and a choice of Budgie, GNOME, MATE or KDE Plasma as the desktop environment.