Sony Bravia Model XR-65A80K cannot find Sonos Arc sound system

1. Sonos ARC S19 connected with HDMI cable, not Fiber Optic.
2. HDMI 3 Arc on TV connected to HDMI on Sonos.
3. I have rebooted both TV and Sonos.
4. I have switched HDMI cables.
5. When I press Settings on TV controller, scroll to Audio output, and scroll down to select Audio system, it says, “Switching audio to external speakers.” Ten seconds later it says, “Audio system is unavailable. Switching to TV speakers.”
6. When I disconnect TV and Sonos from power for 2 minutes, and plug them back in, it says, “Switching audio to external speakers.” Ten seconds later it says, “Audio system is unavailable. Switching to TV speakers.”
7. In the Sonos app on my iPhone, when I go to Home Theater > TV Setup, it says, “Let’s get your Sonos connected to your TV.” After the required steps it says, “Audio System not connected.”
8. The four tiny white LEDs on the Sonos sound bar indicate it is working properly.
9. When I go into External inputs > Manage inputs, all four HDMI ports are set up properly.
10. When I go into External inputs > Bravia Sync settings, BRAVIA Sync control is enabled.
11. When I go into External Inputs > BRAVIA Sync device list, HDMI is set to AudioSystem. I have clicked Enable a couple of different times. Doesn’t do anything.
12. When I go into Display & Sound > Audio output, I click Speakers > Audio system (change from TV Speakers), it says, “Switching audio to external speakers.” Ten seconds later it says, “Audio system is unavailable. Switching to TV speakers.”
13. When I go into Display & Sound > Audio output, I have tried to enable or disable “Auto” eARC mode. No difference.
14. When I go into Display & Sound > Home Theater Control, I see a list of compatible audio systems. The Sony ARC Model S19 is not in the list--but it used to work.
15. When I switch the SONOS cable connected to HDMI 3 ARC to HDMI 4 instead, to get regular (non-ARC) sound, it says, “Switching audio to external speakers.” Ten seconds later it says, “Audio system is unavailable. Switching to TV speakers.

Is it time for me to take these Sony products back for a refund? They are still under warranty.