HomePod Mini for Home Theatre setups

I'd like to purchase 4 HomePod Minis to link into a surround sound system. Since Apple has not yet paired the minis for use with off-brand amplifiers, is there a way to use Apple TV 4K or AirPlay2 for sound set up. It's complicated I know. Or do you know of something tied into HomeKit that might work?

I wish Apple would get into the Rec/Amp business by partnering with one of the bigger manufacturers. They'd sell a ton of HomePod minis.

My other alternative is Sony's SRS-RA5000 or 3000 wireless.