Two Sonos Play in stereo mode connected with tv via usb-c/aux adapter

I wouldn’t expect them to. Most TV’s don’t output a stereo signal via USB. And even if it did, you’d need to deal with the delay on the input, which would make synch between the audio and video difficult, if not impossible. 

You could use one of the TV's outputs, converted to analog stereo and a 3.5 mm audio plug.

Connect that to the Sonos audio input converter and your Era.

You would still have the echo/delay issue.