With so many devices, distributed all around your Home, I would personally recommend you continue running them in wired SonosNet mode, it seems you are doing that already … the difference in the connections and how the setup works are explained in this Sonos Support document:

https://support.sonos.com/s/article/3235

When opting for SonosNet (wired) mode, I would also suggest doing the following:

• Set the routers 2.4ghz WiFi to the least used fixed ‘non-overlapping’ channel 1, 6 or 11 and choose a 20MHz channel-width
• Set the SonosNet channel in the Sonos App “Settings/System/Network” so it is at least 5 channels away from your chosen router channel.
• Remove the WiFi credentials from the "Network/Wireless Setup” in the App as those are not needed when running on SonosNet and it will stop your devices hopping between SonosNet and your WiFi signal, although omit this step if using portable devices ‘Move’ and/or ‘Roam’ as they require the WiFi credentials to work… they do not use SonosNet for their connection.
• Ensure all Sonos products, particularly the wired one is at least 3 to 4 feet away from other Wireless devices including the router and other access points.
• This final suggestion is optional, but often worthwhile... Consider adding the Sonos IP addresses to the local routers DHCP reservation table, as that too will improve stability, particularly during updates and reboots of the local network.

Hopefully those few suggestion will assist to reduce interference… I also recommend checking out these two ‘hopefully’ helpful links too:

1. WiFi Interference
2. Wireless Interference Video: Wireless Interference and Sonos

That last one, static/reserved IP addresses was the solution to my system instability.

If you look at your Network Matrix you can see which wired devices are being used to link to wireless ones. You can also see noise and connectivity issues. It is covered in a lot of posts here if you need more help in reading it.

I wired my easy to wire Sonos, that and putting them on their own channel helped. I found my Boost was not being used and as I had no weak areas that it was worth moving it to so I took it offline.

I had my security camera system running wireless, it ran the use level of the channel it was on up to over 70% and everything on the channel, to include the cameras suffered from the congestion. Putting the cameras on their own WiFi channel helped. Camera vendor suggested I had too many cameras, too high a resolution and too high a frame rate to make sharing a channel work well.

Thanks for both answers. They seem to make sense and to be on target for my issues.

Unfortunately, my knowledge and skills aren’t adequate to implement suggested solutions.

I’ve joined Best Buy’s Geek Squad program and someone will visit the house in a few weeks.

I am able to produce a matrix and it shows several speakers in red. But that is where my limited talent begins and ends.

I really appreciate the overviews provided by your answers and I will show them to the Geek Squad reps when they come.

The red cells point to areas that need attention. Note that the matrix is a static view. Refresh the page to review at different times of day or after any layout changes. BOOST’s are easy to move. 

How are the non SONOS wireless clients performing?

While EoP (Ethernet Over Powerline) is generally my last choice for networking, sometimes it is the magic bullet. In your high interference environment EoP is probably the best bet. Typically, one EoP unit would be wired to the network and others would be attached to red cell, otherwise wireless SONOS units. EoP has its own quirks. Large appliances such as air conditioners on the same circuit as EoP can cause issues while running. Don’t power an EoP unit through a surge suppressor and avoid sharing an outlet with with a surge suppressor. You’ll notice that your electrical panel is arranged in columns. EoP works best for outlets in the same column. Finally, EoP does not usually work well if there are multiple electrical panels. There are work arounds for this, but they can be messy. That’s one reason why EoP is my last choice. The very latest EoP units are much improved over the older units. Avoid “deals” on older units.

Amazing simple solution implemented and is working. A Comcast tech came out and called a Sonos installer friend. The friend recommended using the basic method: Only one speaker connected to the router. This worked.