if you're only using it for Apple Music, the music app on the Mac or the phone can act as a remote for the player in the HomePod, as opposed to playing on the Mac/phone and air playing to the HomePod. Using the remote mode gets rid of the delay.
but for system audio, everything basic75 said is spot on.
depending on the app you're using on the Mac, there is some built in "magic*" to delay the video on the Mac screen to match the audio coming out of the homepods, but think it requires them to use apple's video player. So Safari, QuickTime, or preview. But this causes a bit of lag when you start or resume playback, or jump around in videos, since it has to delay what you're seeing until you hear it.
I've got a Sonos roam, that can do either airplay or bluetooth, I was doing some stuff that required me to jump around in videos a bunch, and airplay was almost unusable, but bluetooth was not horrible.
I believe the Sonos roam, move, era 100, and era300 can do a stereo pair in bluetooth mode, but they must also be connected to wifi. (so your Mac uses BT to one of them, and then it uses Sonos audio to send the other channel to the other speaker) both speakers would need to be the same model. The Era100, era300, and move gen 2 also have an optional audio line in adapter (there are versions with and without ethernet if you don't want to use wifi)
*otherwise known as a workaround to make it appear to suck less.