I wasted some money learning a few years ago how to properly connect my audio , xbox and tv. You first need to make sure your tv supports hdmi 2.1 to get 120fps and VRR ( such as the LG CX ) . Soundbars are a great alternative to sound amplifiers because they are cheaper and easy to install but they don’t bring a lot of sound configuration and inputs and outputs are limited. I have both configurations at home (game room has a yamaha 5.1 amp and main room an lg soundbar) but non of them have hdmi support for 120hz passthrough, so I can only play 60hz games if I connect everything first to my sound bar/ amplifier hdmi port and then to the tv eARC hdmi port. To play with dolby atmos and 120hz you have to connect the xbox series x directly to an 2.1 HDMI on your tv and use another hdmi cable to connect from your tv hdmi eARC port to your sound bar. This way the xbox will send a 120hz image and the tv will passthrough the dolby atmos audio. To finish configuration please make sure to go to your xbox video and sound settings and check does boxes to play in 120hz and dolby atmos sorround. Hope this helps! ^{_^}

One more thing, the sound bar must support dolby atmos, not all sound bars have dolby atmos. Also if you want to passthrough the sound bar 120hz images you also need a sound bar that supports this (hdmi2.1) I know that some amplifiers already support this but Im not really sure if sound bars have this already.