Over Saturated In 2160, not 1440 Or Lower

[editordb-ux]

On one TV, when viewing on YouTube, my project looks great up to 1440p, then goes WAY over-saturated in 2160. Doesn't look like this in Final Cut, Quicktime Player, on my iPhone 12, iPad Pro or even my 4K LG TV from 2020.

But on a slightly newer TV that is 4K and other 4K content via YouTube looks great. It's just my project at 2160 that it falls apart.

Workflow:
I had a Black Magic Film To Rec 709 LUT embedded plied in the clip (not sidecar)
Decode - Eighth
All other options are UNCHECKED so they stay the same as when I recorded
ISO 200
Color Science 5
Color Space Blackmagic Design
Gamma Blackmagic Design Film
Gamut Compression: Enabled

FCP 11.1.1
Library Settings: Standard Gamut SDR
Project Settings 3840x2160 / 23.98, Rendering in ProRes 422, Standard Color Space
I don't have the BRAW Toolbox effect applied to any clips... because I wanted to shoot clips that wouldn't need any major color correction. I have basic color correction from the built in color correction tools to tweak brightness and contrast.