On my home network, the HomePod Mini's demand to use both IPv4 and IPv6 is what I'm thinking is contributing to the unreliability of my stereo pair. My ISP doesn't provide me an IPv6 address, so my home router and pihole both seem to struggle with the HomePod Minis. My original HomePod doesn't have this issue.

What I'd really love is if my HomePod Minis stopped assuming the primary HomeKit Hub role and instead let my Apple TV connected via Ethernet handle all of the requests. There's no way to select a device to be the primary hub as far as I can tell.

...Why does a lack of external IPv6 address cause a problem within your home network?

(I'm genuinely willing to believe it could, because I've seen stupider problems personally, but it does seem like a weird one.)

My consumer mesh router takes an all or nothing approach for IPv6 settings, which causes problems, and there's no customization of IPv6 DNS settings.

I've been meaning to take an old Netgear router, put dd-wrt on it, and then put that between my cable modem and the mesh router.