monitor permanently damaged?

[crais]

Hello!
Recently I'm having some issues with my monitor (BenQ XL2430T + AMD R9 380X ASUS STRIX, Windows10x64) and I'm afraid I might have permanently damaged my monitor with CRU's or AMD Radeon's custom resolutions.

I have mainly used 1440x1080@120Hz, 1280x960@120Hz and 1024x768@120Hz, scaled to fullscreen via DisplayScaling and it was working just fine (beside a few occasional "Out Of Range" notifications which were resolved by turning the monitor off+on) until yesterday, when the monitor failed to display anything (black screen) after being idle for a while.

Now, whenever I try to set the refresh rate above 60Hz (100Hz, 120Hz, 144Hz), the screen scrambles and becomes unusable. The issue occurs on all resolutions. The monitor works just fine at 60Hz though.

This is what it looks like:
   
   
This is the service menu:
   

I have tried the following things to resolve the issue:
- switched to DVI-D cable
- switched back to DisplayPort cable
- reinstalled AMD Radeon (clean install)
- uninstalled all graphics drivers with DDU (+reinstall)
- reinstalled .inf file from BenQ support page
- reset-all via CRU
- reset to factory defaults via OSD
- tried various resolutions/timings via CRU and AMD Radeon
- tried AMD/ATI Pixel Clock Patcher
+issue also occurs with integrated Intel GPU (HD Graphics 530) @ DisplayPort

Is it possible that I have permanently damaged my monitor or might there be another cause/solution?

Any help would be sincerely appreciated!

Greetings