There are several potentials here. 

First, Sonos tends not to play well with many mesh networks, due to the need for all Sonos devices to be on the same subnet. Usually, the recommendation is to run a ‘wired’ system, with at least one Sonos device wired to the ‘root’ device of the network. It’s not clear from your post how your system is connected, nor which mesh router you have deployed.

It is also possible that your system is dealing with duplicate IP addresses, something that can impact both wired devices as well as WiFi connected devices. The quick and dirty way to fix this is to unplug all Sonos devices from power, and while they’re unplugged, reboot the router. Once the router comes back up, you can plug back in the Sonos devices. 

Those two potentials cover probably 95% of what might be going on. It’s extremely unlikely the different types of speakers you have would affect this in any way. 

Thanks!  could this be accomplished by plugging a boost network extender directly into the root device?

You can either cable a speaker to your main router/mesh primary hub, (keeping the speaker at least one metre away from that router/hub), or you can add a Sonos ‘Boost’ to the system and do the same with that device instead.

Both of these things have the same effect of moving all the Sonos products in the system over to a SonosNet signal connection, which is often recommended by many here when using a WiFi mesh based home WiFi network.

Once the system has been switched to SonosNet, if not using any Sonos portable products (Roam/Move) it’s also then worthwhile removing the stored WiFi credentials from the Sonos App network settings - See this LINK for additional info. on how to go about doing that.