Why is AirPlay from iMac to HomePod Mini unreliable?

I recently factory reset my iMac and bought a new HomePod mini. I'm trying to airplay from Apple Music, but it rarely works. I've had this problem for YEARS without any long-term success. I can airplay to the HomePod minis on any other device (iPhone/iPad), but the Mac . It just doesn't work half the time. And I say this as someone who works in the field. It's not like I'm a boomer trying to figure out how Aiarplay works. So dumb.

[Edited by Moderator]