HDR and Dolby Vision for Gaming no longer working on Xbox Series X

So in january of 2023 I bought a brand new Hisense 65 inch 4k HDR (Dolby Vision) TV and a Xbox Series X (previously had a 4k non-HDR tv and a series S). I of course set up the HDR in all its glory and was amazed at the difference.

Suddenly, in August of 2023, the HDR randomly just quit working. I have not changed HDMI cords, or ports on my TV. My TV displays a HDR logo/icon in the top right of my TV when it is enabled (usually when booting up a game that uses it) and it quit popping up. So I went to investigate.

I went to look at my settings under "Settings > General > TV & display options". From there the first thing I noticed was that the "Calibrate HDR" box in the setup column was missing entirely. Second, when navigating to the "Advanced" column and going to "Video modes", and "Allow Dolby Vision" and "Dolby Vision for Gaming" are both selected with a checkmark, but "Allow HDR10" and "Auto HDR" are both greyed out and not selectable. In addition to this, I very specifically remember having to select the "Allow auto low-latency mode" option in order to play games with no input lag, while playing games in HDR but this setting is also greyed out and not selectable anymore.

going back to the "Settings > General > TV & display options" screen, and selecting "4K TV details" under the "Setup" column, under the "Playing games" potion of the screen it says "Your TV settup doesn't support HDR10 for gaming. Games won't be shown in HDR" with a red cross-out circle on the left. and it also says "Your TV setup doesn't support Dolby Vision for gaming" with the same red crossed out circle on the left. - These settings used to have a green check mark next to them (or at least the Dolby Vision one was green for sure)

When scrolling down to the "Watching movies and TV" potion of the page, it says "Your TV supports Dolby Vision." with a green check mark on its left.

I can 100% confirm that this specific xbox, on this specific 100, with the same HDMI cords and ports, were allowing me to play games in HDR. I have tested it with multiple games such as the Wither 3, The Division 2, Diablo 4, Assassin's creed Odyssey, Imortals Fenyx Rising, Generation Zero, Forza Horizion 5, and MANY others, and I was always able to calibrate the HDR setting in game, as well as on the "TV & display options" screen. Recently, I have tried to turn HDR on in both lies of P, and Armored Core 6 and the setting is greyed out in game as well and I cannot turn it on. I tried to set it up with my old Series S that my brother-in-law now uses and I got the EXACT same results.

In addition to this, my TV also has a PS5 hooked up to it, and the HDR is working just fine on the PS5. I am trying to attach multiple pictures of both my XBOX series X settings screens and the PS5 with the HDR notification popping up on my TV to show that it is indeed working on that console, but the image uploads are failing on this MS questions page. I will try to add them in an edit.

Xbox is my primary system and the PS5 is technically my fiance's and she only uses it for a flew select console exclusives as she also primarily plays on her own Xbox series S with me.

Does anyone have ANY ideas on how to fix this?

:)