As stated in the following link, Sonos requires WiFi. 

https://support.sonos.com/en-us/article/sonos-system-requirements

Also, using a Sub with a Playbar requires the Playbar's WiFi to be turned on.  In short, if one intends to eliminate the use of WiFi in the home, one should not use Sonos.. 

You bought wifi speakers to use without wifi??? 

Best you can do is use just the Playbar over optical link to tv. Set TV Autoplay to On. Then use the tv remote to control volume. I’m not sure if you can Ethernet-connect the Sub; if not, sell it. Don’t try to stream music or control any EQ settings from a phone, as the app communicates via wifi. The PC app will give limited functionality. 

If you connect your Playbar to Ethernet and your router, then the router should merge the wired and wifi connections into a single network. With the phone not connected to that local network you must use the much more limited Web App from a web browser or one of the old PC or Mac apps.

Not on topic but given all the horribly bad information being spread to gather advertising revenue I feel it useful to add: Seems rather silly to avoid trying to avoid wifi but wanting to use Sonosnet that is so close to the same thing they are hard to tell apart.

You might also question the dangers of a cell-phone stuck to the side of your head or tucked in a pocket near some rather important and RF sensitive organs, with the internal cellular radio pumping out RF energy. Compared to a Sonos speaker a couple feet away from you it is putting more energy into your body.

Not telling you safe or dangerous, that is your decision, just suggesting getting good information and making consistent decisions. You need to consider all sources of RF energy yours and that from folks around you and mitigation strategies if you are serious about this.

You state: “wifi turned off on the play bar thru the app , then to my understanding , that creates its own wifi to connect to my sub”. As said above Sonosnet is also WiFi. And, also important “WiFi off” on Sonos means no radio connection at all, so no Sonosnet or the dedicated 5Ghz network to Sub or surrounds either.