Can I stream system audio from macOS to multiple Airplay 2 devices at once?

I can do this from iOS. I used to do it with with the old Airplay using some third-party software from Rogue Amoeba. The Apple(TM) Music 'App' on my Mac can do it. I've read about creating some Frankenstein multi-output thingie in the MIDI section of settings, or something like that -- not interested. Does anyone have a convenient solution to this obvious use case? I'll take a third-party solution again, if need be, since it seems like Apple is once again denying functionality to steer users toward their profit channels (the Music App in this case). I have a ton of Airplay 2 -capable Airport Expresses which I Hoovered up on Ebay. They're great, and I'd just like to be able to stream to a bunch at once from my Mac using the audio source of my choice.