(Help) White reduces brightness CRT monitor

Hello everyone,

I have just gotten a CRT monitor (Iiyama pro 454) and was encountering a problem: The brightness drops significantly when I increase the amount of white on the screen, for example when I open a white window (e.g. word or my documents). The white then becomes gray.

A video: https://imgur.com/a/3ydLEzo (The effect is more pronounced IRL because my camera automatically changes its brightness making it look less worse than it actually is)

Is that normal?/Is there a way to solve this?

The contrast/resolution are already at 100%. When I reduce them enough, I don't have the problem anymore but the screen is too dim for me in that case.