HomePod can't stay connected

I have 6 HomePods and one HomePod mini in my network. The music stream I run from my Mac routinely drops connections to them. Had them since late 2020 and it's been getting progressively worse over time.

They seem to behave better when I source the connection from my phone and limit it to a single (or single pair) of speakers. But when I try to go 'whole house', the connections drop all the time. They're all configured on the same WiFi network. I've done multiple factory resets -- with the subsequent updates being downloaded to them -- but the problem persists. I've got a material investment in these things and I don't want to dump them, but I'm running out of patience. When is Apple going to address this problem?!