Since PS5 is confirmed to work with the buggy HDMI 2.1 chip at 4K/120Hz/HDR/YUV422, I think it will put pressure on Microsoft to update the software or firmware to have option to workaround the bug if that's possible.
This is backwards. Sound United is spinning the story putting out their PR videos making it look like there was no problem with PS5. They rolled out their smooth-talking marketeer in the videos who can, if necessary, make a compelling pitch 10-bit audio seem like the greatest invention and a gift to audiophiles.
Meanwhile, PS5 is under pressure from their users for capping their bandwidth without telling anybody which is what makes it work with 2.1 AVRs with the Panasonic chip. They will likely need to remove that cap soon for marketing reasons.
The real issue:
HDMI 2.1 specs support up to 48Gbps bandwidth.
40Gbps bandwidth is sufficient to do 10-bit HDR YUV 444 at 120hz.
Given the processing power needed to go above 40Gbps. most consoles including the X Box aren't likely to go above 40Gbps in the current generation. And when using 40Gbps they are not compressing the streams since that requires more processing power than they have available without affecting refresh rate.
Panasonic 2.1 chips cannot do uncompressed streams. This is a limitation that current generation of HDMI 2.1 AVRs with that chip have. There is no way around it.
When upstream devices are capped at 32Gbps, they do compressed video and cannot do 10-bit HDR YUV444 at 120hz and so there is chroma sub-sampling needed (the audio equivalent of the limitations of downsampling a high sample rate audio stream to fit the limited capability of the wire protocol/downstream device). So color hi-fidelity is lost. That means you have a choice between high sample rate (smooth picture) at lower color fidelity (lower bandwidth) or vice versa. The current Panasonic chip based AVRs will all have this compromise.
This is why the customers of PS5 are dumping on Sony when the news that PS5 bandwidth was capped came out recently.
XBox does not have this cap and so does 40Gbps with uncompressed streams (compressing them would require more processing power than they have available). Since most TVs are capable of 40Gbps bandwidth, PS5 users are screaming that they are not getting the full benefit of HDMI 2.1. LG which had capped their TVs at 32Gbps also came under fire for this reason.
But if the console or card sends out uncompressed 40Gbps, then it will blank out for a pass-through via the AVR with the Panasonic chip rather than degrade gracefully.
Nvidia RTX 30-series cards can do full 48Gbps. But the drivers have a setting to downgrade it.
I don't know if this is a problem with HDMI 2.1 specs or its implementation but I am surprised that there wasn't a HDMI handshake negotiation between source and destination to figure out the max rate that can be supported between source and destination and so degrade gracefully than lead to this blanked out screen situation.
The solution is to manually cap the source at 32Gbps if possible when the source is capable of higher bandwidth. This will avoid the blank screen problem when passing through the AVR.
So, if there is any fix at all for Xbox, it would be a setting to specify less than its maximum 40Gbps (or max YUV422 no HDR in 120hz mode, etc). That is, in effect, allowing the user to voluntarily downgrade to accommodate the AVR! I don't see XBox group rushing to do this as most of their users probably connect it directly to the TV anyway.