I had an XBSX connected to my soundbar and could enable and utilise Dolby Atmos.

Recreating the same connectivity with a PS5: PS5 > soundbar > TV input , the console will allow me to select Atmos but nothing from the rear speakers.

Is there anything else I need to be concerned with?

Is the cable that is supplied with a SLIM PS5 HDMI 2.1 and is adequate to support Atmos, or do I need to get a HDMI 2.1 cable?

Thanks