I went looking for a file manager with miller column on Linux once. It seems to be an extremely rare feature. With how popular column view is in Finder, I don’t understand how it hasn’t made its way to other platforms as a commonplace feature.
I had the exact same journey as you, I even very nearly install GNUStep because the file manager had miller columns.
I even started to think that perhaps Apple has an active patent on it or something.
(this happened with the Genie Lamp minimise effect on Compiz/Beryl- why it needed to have at minimum 3 "waves" before it minimised the window; though you could obviously patch it out).
FWIW I found Ranger (TUI) and Pantheon (ElementaryOS) that supports it, if you're still looking.
