HomeKit Unstable and Hub Connections Destroying WiFi Bandwidth

I am struggling to keep HomeKit with about eight HomePods and two ATV potential hubs from frequently destroying my WiFi speed—even with a brand new Eero 6E Pro and five extenders. It seems that even just adding a HomeKit accessory causes a major wifi slowdown—with cries for help from my work-from-home extended family. I believe what I see happening is that adding a new accessory or other undefined HomeKit events cause a significant stress on the WiFi bandwidth. Then with decreased bandwidth, a vicious downward spiral starts where other "Standby" hubs start dropping out until I frequently get the no connected hubs message—and at the same time internet connectivity is essentially frozen for everyone. Weirdly, this stage correlates in the Eero app with wifi signal strength indicators to the extenders falling from four bars (max strength) to very low levels. Rebooting cable modem and then Eero Gateway takes the house back to a fast signal after a relatively prolonged time, but HomeKit remains fragile with frequent loss of accessories.

This is in context of an incoming Xfinity wired data rate to gateway that remains great: 2.5 Gbps, and the Eero system offering excellent speed everywhere until HomeKit brings it down. I removed some of the HomePod Minis as I read that they could be the problem. I believe I witnessed plugging one of them in causing the above death spiral. I tried unpairing stereo HomePods. I assigned reserved DHCP numbers to all the hubs (all the suggestions you read online, except I have not tried separating the HomePods to the 2.4 Ghz channel.) I have an extensive HomeKit set up with many Meross Wall Switches and around 100 total accessories, including five Logitech Circle View cameras and a Eufy Homebase 2 with two cameras—all standard equipment from the regular HomeKit suppliers. It worked well for many months but with mild instability, probably from inadequate wifi extenders. Recently, out of desperation, I deleted my entire Home setup to give the WFH family a stable internet. I am now trying to rebuild it, but very frustrated by the above fragility. Today I relinked one wall switch and it triggering a major slow down and briefly loss of all hubs, necessitating rebooting the modem and Eero gateway.

Possibly related but of uncertain importance: while installing some of the switches and smart bulbs, I have often seen the HomeKit Mismatch dialog box appear and then disappear. One of them stayed long enough to read something about one of the standby hubs being on a different network—not true. I also have had messages appear saying that "Cannot Link to Default Room, make sure it is powered up". (Maybe this comes from the network freezing up when you are adding an accessory and it is in that intermediate state before a room is assigned -- somehow it thinks there is a potential hub there. From when I added back the HomePods? Nothing in Default Room now.)

Thank you for reading this. I am an experienced Apple user since the late 1970s and technically inclined. Any help would be greatly appreciated as I have spent many, many, many hours, and money on router and extender upgrades trying to fix this. It does seem to me that HomeKit is unstable and the HomePod (or less likely one ATV hubs) are at the heart of my problem. Deeply appreciative,

Bill Convey

Ps: The Eero Pro 6E IS compatible with HomeKit, they just dropped the granular security option for HomeKit offered by the previous models.