Question Screen flicker/weird glow effect on monitor

Nov 2, 2019
I have this weird screen flicker problem, but only in games and only in dark areas. It is pretty obvious, although its nothing like a screen tearing issue. I tried messing around with the settings, changing monitor brightness etc. but nothing helped. I've also checked if it was running in native 1080p resolution and 60hz, and yes, it was. It happens in more than one game, but as I said only in dark areas. Not visible outside of games. Even dark scenes in movies are fine.

And the second problem is a weird glow effect around light sources. This one is both in and outside of games. For example, a lamp in a game has a very visible, ugly glow around it (not intended for sure), same thing in movies too. I have a pic here to help you understand it better. My monitor is an Asus 21,5'' VP228DE D-Sub monitor.
Here is the pic : View:

My specs are : i5 9600k cpu, 16 gbs or ram, 1tb crucical nvm2 ssd and gtx 960 4gb (until I can afford a better one).

Although the gpu is old, I never had this problem in my old pc and old 720p monitor. What could be causing this ?