Are any of the PLAY:1’s configured as surrounds?

It is a complicated mess. If you have a Sonosnet compatible wired device with wifi (the internal radio) active you are going to create a 2.4 gHz Sonosnet. If you disable wifi (actually the internal radio) then Sonosnet won't be created by that device but you will have also disabled the 5 gHz Sonosnet used to conect to subs and surrounds from that device.

The disable wifi option is only available on devices wired to Ethernet and Sonosnet compatible.

If the Ethernet is disconnected the radio is enabled, no matter the setting.

Sonosnet 2.4 gHz is only available on some Sonos, not your Roam.

I'd recommend avoiding the mess and going full wifi, no Ethernet and seeing if that works. If it doesn't then open the Ethernet/ disable wifi can of worms

There are current discussions that have more detail. The forum search is horrid at finding new content so check every post and ignore any old information. Using an external search with the site: switch and looking at six months or newer might be less frustrating. 

Try here

https://en.community.sonos.com/speakers-228992/ethernet-vs-wireless-or-a-combination-of-the-two-best-route-to-go-6930583

I cannot find the disable wifi option on any device - not on my PlayBar, nor on one of my Play:1s that is ethernet connected.   To be fair, I don’t really want to disable the radio completely, nor do I really care if SonosNet is enabled, but what I want to do is have the devices use WiFi instead of SonosNet.  It seems like they insist on using SonosNet rather than Wifi.

So if I understand correctly from previous reading and here, if I disconnect ALL devices from ethernet, then SonosNet will become unavailable (makes sense) and all devices will switch to using Wifi.  This is an option for me, but I’d rather keep the few devices that have ethernet available to them, connected.

It makes no sense to me that Sonos wouldn’t make it easier to switch between using WiFi vs SonosNet.  I agree, it’s a mess.  Thank you for the info.

My understanding is that the network code always seeks the lowest latency between targets. If this is true, it certainly suggests that SonosNet is ‘faster’ than going to your WiFi router. However, it’s unknown if this is just the WiFi signal itself (SonosNet is one of the earliest robust mesh networking, from what I can tell), or a slight delay introduced by your router while handling the packets. 
 

Frankly, if it is working the way it is, I wouldn’t mess with it. I’d change that only at the point that there is an issue. 

Well,  that’s just it.   I have a couple of speakers in an area of the house that has been a SonosNet issue for some time.   With copious amounts of testing I’ve never gotten those two speakers to be reliable.  However, I do have quite reliable WiFi in the house, including that area of the house.  Hence why I’d like to make the switch, I’m tired of having these two speakers with disconnect issues.​​

I don't have a Playbar and my Play 1s are off-line so I can't help directly on them. 

On my Play 5 (gen 2)

Settings

Play 5's Room

Products - Play 5

Status

Connection

And the disable/enable option is there:

What really makes sense and has been discussed is having an option to disable ONLY the 2.4 gHz Sonosnet if Ethernet is connected. Internal radio and all other wireless radio functions would remain available.

Then you could wire all the Sonos you want to, but keep everything else on the home wifi.

The disable wifi should stay as it does have a purpose in a few situations but should be related disable radio so it is clear what is actually done.

Actually, based on the test I just did a moment ago, I think I disagree.  I think you should still be able to disable SonosNet on the devices, or across the entire system, leaving wifi and ethernet enabled.   Just for fun, I tried the suggestion of unplugging my two speakers that were wired.   As soon as I did that, my entire sonos network flipped over to using Wifi, which was great - every single node went green in my network matrix, with the exception of my playbar which is in the basement and farthest away from my wifi access point.  It kept hovering between orange and red.   So then, just for fun I plugged the playbar back into ethernet.    The moment I did that my entire sonos network flipped back over to using SonosNet again.

My point being that lets say I have a few devices wired up and have the radio disabled, that’s fine.  But for those others that still have the radio enabled including with SonosNet, that means that the moment someone either accidentally or on purpose plugs any one of those speakers into a switch port, the entire rest of the wireless network will flip back over to using SonosNet before you have an opportunity to disable the radio on that speaker (and assuming the person plugging in the wire knows to do so).

I think actually the best answer is to allow you to disable SonosNet (while leaving wifi enabled) on a speaker by speaker basis - it can’t be that hard for them to implement.  Then, if you have one speaker that really is in a bad wifi spot with not wired access, you could enable sonosnet on it and one other relatively nearby speaker to bridge the gap.

Based on my above test, I think for now the simplest answer is for me to keep everything unwired to force WiFi usage, and instead get my act together and improve general wifi performance in my basement.  :) 

Wiring the Playbar and disabling Sonosnet on it, as long as there are no surrounds or subs should work for you.

Being able to disable incoming 2.4 gHz Sonosnet while leaving Wi-Fi and the 5 gHz / surround Sonosnet active would make your older speakers work like the Eras, not at all a bad idea.

the problem is that I don’t have that option to disable the radio on the playbar, even when it’s wired up.   If it would let me I would. But oh well, leaving it unwired gives me incentive to shore up my basement wifi, I can live with that .

The playbar is so old, maybe the option is only in the :1400 internal web pages and not the app?

Hopefully someone that has one can help you find it if it wasn't where I mentioned above.

Agree. You have cabling to basement, that you unplugged from your Playbar. Unplugging all your Sonos devices will free up an additional 2.4GHz channel for you new AP. Don’t bother with latest WiFi7 APs, WiFi6 APs are fine.