Game in the game view window is pixelated while in scene view it's okay

The problem can be easily understood by seeing this 1 or the image below.

I’ve already tried this, this, this, anti-aliasing configuration stuff and the problem isn’t about zooming in the game view. The shimmering can be viewed from afar.

Any help is very much appreciated.

You have the scale on the game window zoomed in, you see that slider in the middle of that window? That needs to be set all the way down to the min value (I think that is 1).