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.
Quakespasm-Spiked does have macOS and Linux builds available, although they may not be as up-to-date as the Windows versions. If you’re good at building stuff from source, you can check out its sourcecode repo.
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.