oOLANGERSOo: UPDATE: I FIXED IT. I tinkered with my graphics settings for a bit and discovered that having dynamic resolution scaling on is what caused the problem.
Goody! :)
Are you playing on patch 1.62?
I'm still on 1.6, and I don't think I even have that setting. Point being with my suggestions above, was that such flickering almost always is a graphics issue, where the game doesn't really know how to properly display something.
This is usually caused by raytracing, shadows, or - as was the case here - upscaling. You may see the same thing happen outdoors, like flickering wall posters, especially when moving the mouse fast side to side, and the fake rendering cannot keep up. This is why I play without any artificial improvement, with both RT and DLSS turned off. I play on custom High settings with reduced shadows.
Another tip: turn off ALL of the Basic settings. Film grain, Lens Flare, Motion Blur etc. All that is doing is distorting the image, making everything look worse.