It saves on licensing fees not having a DA decoder. Probably why they also aren't doing Dolby Vision. Also they are focusing more on games than being a media player. And also they will be wanting to push their own custom 3D Audio from Tempest Engine.Yes I can plug it in directly which probably will now.
I have it all set up with the blu-ray playback, kind of ridiculous that sub £100 streaming sticks can handle deciding Atmos but this brand new expensive giant router can't! XD
For games and streaming services, seen as you are plugged directly into the bar, in the general PS5 System Audio settings, you should set the audio format to Linear PCM. Apparently, if you want full 5.1/7.1 surround sound signal to the bar you should select HDMI device type to either soundbar or AVR and then set the speaker configuration to 7.1.
Hope this helps