I have 13 Sonos speakers all on WiFi, and they work perfectly. None are connected to Ethernet. No special configuration.
I did try putting Sonos on my IOT network but consumer devices are not designed to work across networks, even if the network switches have settings to help - mDNS, discovery, etc. - so they are on my main network. I have a LOT of IOT devices, family and friend on other VLANs/SSIDs. My family had an engagement party for my son - 80 people - and at least 20-30 people were on the WiFi inside the house and in the backyard (mostly in the backyard) for the day and evening. I have:
- A Sonos Arc soundbar, 2 Era 100 satellites, Sub (gen 3). The Arc soundbar creates its own WiFi network for the devices that are configured to be part of the soundbar system. AFAIK, this cannot be changed. I have tried, but its turned out not to be necessary. AFAIK, it would still do this if wired. I originally thought I had a defective sub because it would not connected to the local AP after unplugging it from a temporary Ethernet connection. Nope, it wanted to be connected on the WiFi network created by the soundbar. I wasted a lot of time on this and even replaced the sub because I thought it was defective. It wasn't. I plan to add two front satellites to the soundbar system eventually.
- I have 2 additional Era 100 speakers that are not part of the sound bar configuration.
- I have 7 Move 1 speakers that I disburse during parties. I have a large backyard and my extended family uses my backyard. One is always plugged in my garage, but it gets moved to the backyard during parties. The others are in a cabinet. I put all 7 out for the parties. I have enough power outlets in the backyard that I can just run extension cords through the bushes so that all 7 are sitting on their powered bases. I think once I let them use their internal batteries as I knew the party (a wedding shower) would only last 5 hours but normally they're plugged in.
I can send music to any speaker or speakers as desired - the Sonos app excels at this. I have sent music (I use Spotify) to the backyard speakers continuously for 12 hours, including all the indoor speakers (soundbar, etc.) without any interruptions. At some point someone usually wants to watch sports so the soundbar, 2 satellites and sub switch from music to whatever is on TV.
I have 3 AP27 outdoor APs, 4 indoor APs (2 AP25 and 2 AP22D), and 3 switches. All my APs are Ethernet wired. The soundbar, satellites and sub are on their own 2.4 GHz network that Sonos creates. The other 9 speakers are on my 5 GHz network.
Like I said, it just works. My suggestion is not to fight with Sonos. I have spent a lot of time over the years fighting consumer equipment that expects to be on the same network. Get it working as it's designed - first. If you still want to bend it to your will - do it after you know it all works.
I hope this helps.