It already sounds like a local network issue, maybe it’s matters linked to the STP and and/or SSDP multicast device discovery, perhaps? Although you have not provided too much detail in your post.

Maybe simply try your setup running on SonosNet, with the chosen channel set to 5+ channels away from your routers 2.4Ghz channel, which also needs to be non-overlapping, ‘fixed’ and ideally with a channel-width of 20MHz only.

Also ensure the wired Sonos product is positioned at least one metre away from the router, or other wireless AP to further reduce interference.

If using only non-portable Sonos products, then remove the network credentials from the Sonos App network settings too as described in this Sonos Support document. 
https://support.sonos.com/s/article/3488

It’s optional, but also helpful, to reserve all the Sonos IP addresses in the routers DHCP reservation table.. if the device MAC addresses are needed, you will be able to view those from the ‘About My System’ area in the Sonos App ‘Settings/System’ area.

So see if those few quick suggestions help to resolve your issue. Notwithstanding your current network setup may have incompatibilities, but we can’t cross that bridge, I guess, until the setup is described in greater detail.

On that optional part in Ken’s helpful post, you could try a temporary solution that does what he’s saying for a temporary amount of time (and perhaps permanent, one never knows) by merely unplugging the Sonos devices from power, and rebooting the router. Once the router comes back on line, plug back in the Sonos devices, which will then ask the router for new IP addresses. Shorter term than defining reserved IP addresses, but an easier test, if you’re unsure how to define those reservations in your router’s firmware/software.

Just a drive by… again