Okay, both devices are through HDMI 2.1. The sound through the aux cable is very low. On a 1-100 scale, both need to be on at least 45, and 45-65 aren’t much on improvement on loudness.
It is not my sound bar, as my volume was around 15-25. 25 was very loud with optical out before.
Can the USB or Type C USB be used to send sound to my soundbar?
I do have an aux cable that has USB C with DAC, I use it for my phone.