Homepod Mini stereo pair keeps disconnecting from Mac

Hey gang

I've recently bought Homepod Minis to run as a stereo pair with my Mac (running 15.4.1). I keep running into issues where the Mac "cannot connect" to the pair even with the Home app running.

I get the same issue with the iPhone (XSmax running 18.4.1) which can't "see" the Homepod pair as an airplay option.

Restarting the Homepods, recreating the pair, checking they're on the same wifi network etc occasionally works but not consistently. The failure to connect keeps recurring at least once every couple of days, which I don't want to keep dealing with.

Any thoughts, or is it time to jack in the "it just works" concept and go buy regular speakers?