Mac mini mid 2011 display issue AMD radeon 6630m

I got a used mac mini. Works fine except; randomly the display breaks. After countless times of rebooting, resetting, hard resetting etc, I figured replugging the HDMI cable sort of fixes it.

Display is Samsung s27d360

I tried HDMI to HDMI, HDMI to thunderbolt, VGA to lightning. Best one so far seems to be HDMI-HDMI cable.

I ran a full hardware test (pressing D at boot), no issues were found.

The monitor works fine with either cable configuration on Macbook air 2012

I got this blue screen after reboot before login screen

I also got it once after the login screen

I randomly get screen dividing / clipping into two

Randomly get grey screen with vertical bars (no pink or green bars)

Is it the monitor? Cables? (They are not Apple original) Firmware? GPU? I really want to keep using this.

I hope someone had similar issues and was able to fix it simply by a firmware upgrade or display setting or a cable or something. Help please.

Thanks