HDR LG OLED C1 "Invalid Format" error?

[heyguyslol]

System Specs:
10900K
RTX 3090 (latest drivers) Gsync-Off, Nvidia CP 1440p 120hz RGB
w/ Zeskit Maya HDMI 2.1 certified cables w/ 25k 5 star on Amazon
32GB RAM
WIN10 (fully updated)
LG C1 OLED (fully updated)

My preferred output settings are 1440p @ 120fps w/ HDR enabled, & Gsync-Off.

Every game I own w/ the exception of "Armored Core 6", runs perfectly w/ my preferred settings ^ enabled, such as:

God of War 2018
Horizon Zero Dawn
Days Gone
Metro Exodus (Enhanced ED)
just to name a few

I'm getting the well known "Invalid Format" error when trying to enable "Fullscreen HDR". Borderless Window works but no HDR. I've noticed in the LG "Game Mode" options that when I enter "Fullscreen HDR" it changes the framerate from 120 to 144. This does not happen w/ my other games it stays at 120. I suspect there maybe a forced framerate lock in AC6 ini file that is forcing a 144hz/fps which is causing the "Invalid Format" error.

To satisfy possible solutions I've tested the games above which run perfect, swapped HDMI ports and cables, also tried lowering the refresh rate to 60hz and then swapping back to 120hz & 144hz.

Is anyone else having this issue and/or found a solution to this problem?

It's clearly a problem w/ how the game is enabling HDR in fullscreen mode because I have other higher demanding games that run perfectly fine w/o any issues. I just wonder if an cfg.ini file could be edited to fix this?