How is the soundbar linked to the TCL TV, are you using a direct/indirect HDMI-ARC/eARC connection, or are you using the Sonos Optical-to-HDMI connector?

The soundbar is linked with HDMI/eARC to TCL TV.

In that case I would perhaps try toggling CEC OFF/ON on the TCL TV and ensuring ‘TV Autoplay’ is enabled in the Sonos Arc ‘room’ settings in the Sonos App and power the TV on/off too.

If no joy with that,  then when you have the Arc room showing on the ‘Now Playing’ screen in the Sonos App, select the TV icon from foot of the Music Sevices tab and check the Arc volume is not muted, or set at a very low-level in the App.

I’d also be tempted to reboot the TV, by unplugging it from the wall for two minutes.