Hi.  Atmos isn’t really a format that can be decoded into PCM… but leaving that aside, please tell us which streaming service(s) you are using, whether they are apps built in to the TV or from an external device.

On the TV, HDMI Input Audio Format should be set to 'Bitstream'. Set Digital Sound Output to ‘Pass through’ or ‘Auto’. eARC Support should be turned on.  (Not all of these may be relevant to your current situation, though)

Thanks, John

Don’t know why but now it seems to be working fine