you certainly can. Omarchy doesn't appear to be anything special, just a tiling WM (of which there are plenty of on macOS: aerospace, yabai, amethyst, etc.) with some preinstalled applications + basic dotfiles. people have been running similar setups for years on macOS
Are you aware that Omarchy is just a bunch of scripts on top of a GNU/Linux distro, which has been available in one way or another for the past three decades?
Lots of developers are tired of being hemmed in and disrespected by Apple. Omarchy gets us back into using an OS made for developers, by developers.