HomePod Minis keep disconnecting from new M1 iMac

Hi, I have two HomePod Minis next to my new M1 iMac, because the audio from the new iMacs is not that great, to be honest. The HomePod Minis provide stereo sound (they are grouped). It is rare now that when I start to play music from my iMac that it will stream and continue playing on the HomePods. For some reason about 10 seconds of a song will start playing, then it just stops. Sometimes the Apple Music player shows that the song appears to still be playing (the scrubber is still moving forward), but there's no sound coming out of the speakers. Sometimes the music just stops playing completely.

I have no idea why this is happening, or why the problem appears worse now since the latest Big Sur update (11.5.1), but it almost never works anymore. I have already tried restarting the HomePods, and resetting them and setting them up all over again from scratch THREE times. While that may fix the problem temporarily, eventually later that day they go back to not playing music again and seem to be unable to stay connected to my iMac even though the speakers are right near it.

I'm guessing based on other threads I've read here that this is a design flaw in the HomePods, because so many others have had the same problem, but I've yet to see a solution. So I'm posting this to see if anyone has found a fix to this problem, because nothing I have tried so far fixes this issue. Thanks.