You didn’t mention specifically which HDMI 2.1 compatible LG model you own, so I’ll assume it’s a CX.
As
bootman mentioned, considering the flaw in the Panasonic chip (which cannot be fixed with a firmware update), there are now exactly
ZERO HDMI 2.1 compatible AVPs or AVRs currently on the market that will support the upcoming gaming platforms.
Right now, the cheapest and easiest solution would be to plug the console directly into the TV and use eARC to bitstream the hi-rez audio back to the audio processor. Since your XMC-2 does not support eARC, your solution would be to purchase a Thenaudio Sharc eARC processor.
The Sharc would plug into the eARC compatible input of your CX (HDMI 2). The HDMI output from the Sharc would then plug into any available HDMI input on your XMC-2. The Sharc adapter will receive the audio from the eARC channel and then seamlessly convert it to conventional HDMI.
Since the Sharc does not support video, your XMC-2 will need to connect to your CX using a different HDMI input (there’s four HDMI inputs on the CX) for normal viewing of your other video sources that are connected directly to your XMC-2.
The Thenaudio Sharc may effectively solve two problems or you... First, pass though audio from your new gaming platform and, second, solve audio issues from your TV apps since using traditional HDMI ARC between your LG and XMC-2 is no longer used or required.
HERE is more information on the Thenaudio Sharc eARC processor. You’ll find that many users are using this exclusively to avoid spending thousands of dollars upgrading what are, otherwise, perfectly good processors and, instead, use the HDMI 2.1 switch of the display.
There’s a thread specifically dedicated to this device over on the AVS forum. You’ll also find references to this device throughout both the C9 and CX threads.
Hope this helps...