Pink screen after update to Catalina

Hi all,

Freshly installed Mojave last week, after some little problems, including the pink screen which i fixed, i updated to Catalina.

My resolution is now correct 3440*1440, but limited to 30Hz (should be 60Hz) and the pink is back again..

The solution i used last time (found here, link to github https://gist.github.com/adaugherity/7435890) i tried again but cant copy the file to the right location.

Even login as root, but lack the permissions to write to the folder.

Search only gives me high-sierra and mojave threads ( with the solution i tried)

vanilla install from reddit guide.

i7700K, HD630, asrock z270m extreme4, 32GB, samsung nvme.

I also lack the audio device. although the correct kext is inserted in "others" folder.

When i use the monitor on my macbook pro (usb-c - hdmi) it functions correct.

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Complete n00b to hackintosh....