Question No 5.1 sound Win10, splitter hdmi2.2 IN/passthrough/optical+hdmi2.2 OUT, 4k 60Hz uhd projector, dolby atmos soundbar

Mar 1, 2020
I have issue because my PC recognize only projector and send only stereo sound (I don't know what format is output from my PC).
I can't force it to 5.1 even splitter is set to just passthrough (I don't want to infect on sound quality with splitter) and optical cable is connected to soundbar and hdmi to projector.
Is it possible to force win10 to send 5.1 sound to hdmi?
Even better, how to make it with Dolby Atmos, when I have Dolby Atmos soundbar?
Thank you.