If you would rather play Quake on macOS or some Linux distro, you can do that! The same Quake pak files and custom content will work on any OS.
vkQuake does have Linux builds available. It will also work on macOS but doesn’t have official Mac builds; for macOS you can either build it yourself from source or, if you have a GitHub account, click on a recent automated macOS build from the “master” branch and download the “vkQuake archive” from the bottom of its page.
Ironwail does not work on macOS at all because of OpenGL driver limitations there. On Linux you can build it yourself if you like; just run “make” inside the Quake directory of its source code.
You may also want to investigate other Quake engines as described in the Quake Engines chapter.
You can get soundtrack music files from any installation of the “enhanced” Quake release, or from a Steam guide.
The Explore More chapter (under Maps and Mods) describes ways to get custom content; it also describes a crossplatform addons downloader/installer/launcher (Quake Injector).
The Launcherless Launch chapter describes how to run custom Quake content if you don’t use a launcher.
Finally, if you’re playing on Ubuntu Linux (or an Ubuntu-like) and consider yourself pretty familiar with your system and handy with the command line, you may be interested in my own setup of Linux desktop integration and Chrome integration for Quake activities.