I finally got the chance to do some more testing and I took these pictures. They were taken with my iphone so please bear in mind that the image looks way better in person. My PJ settings were High Lamp, BT2020, 1000 Nit Custom Curve. Vertex settings: Automix, LLDV EDID 8 LG C8 etc. There were NO red tint to the image and, like I said, the pictures just don't do justice to what I see on screen. I am convinced that the ATV is doing something different/better than the disc players (Panny UB820 and Sony X800M2) as the results are completely different.
PS I don't know why my pictures are sideways and I don't know how to get them right side up. Hopefully, they can still serve to give the general idea as to what I am seeing in my setup.