I do actually have this setup going with a Cable Matters adapter [1] + a custom firmware I found [2] and

> chroma/RGB 4:4:4 + HDR + VRR/Freesync + 4k,120hz for their Linux PC on a TV

works great now on my LG C4 TV with Bazzite's gaming mode, though:

* 144Hz is unstable

* 12-bit color is unstable (10-bit works fine), and gamescope doesn't have a way to limit color depth (kwin does), so I had to put in place an EDID override

* in the EDID, limiting the FreeSync range to 60-120Hz (which should still allow frame doubling/tripling) seemed to be better -- the default 40Hz caused a bit of flickering because the AMD driver would drop the refresh rate down to 38.5Hz or so.

Should write about this in more detail.

[1] https://www.amazon.com/dp/B094XR43M5

[2] https://forum.level1techs.com/t/it-is-possible-to-4k-120-hdr...