Until then, there is a kind-of hack or workaround that allows you to set up two HomePods or two HomePod minis as computer speakers. We're hoping that Apple will roll out a macOS update in the near future that will allow you to designate two HomePods or two HomePod minis as your computer speakers. It's a little bit baffling considering it's actually really easy to designate two HomePods or two HomePod minis as the default TV speakers with an Apple TV you can use a single HomePod or HomePod mini as the lone TV speaker for your Apple TV, too, but it just won't deliver that superior stereo sound.
You can designate a single HomePod or HomePod mini as your Mac's speakers, but not a stereo pair.