That's my exact thought process. I put LDS at Android because they do identify as Christian, but we are really stretching the definition of what technically counts as Christian.
Honestly I don't know as much as I ought to about UU, but I didn't think that they generally identify as Christian.
To stick to the theme of my chart, since Unitarian Universalism is non-trinitarian it would likely need to be a Unix-like OS that isn't Linux.
I would give it OpenSolaris. (And that's a compliment.)
Arch is the denomination that is super proud of itself, despite being messed up for most people.
OpenSuse is Baptist due to it's general reliability and flexibility.
ChromeOS is Southern Baptist because it's barely recognizable as Linux.
Pop_OS! would be United Churches of Christ. Derived from Ubuntu, and generally accepted as reliable and easy for newbies.