Question External monitor crashes occasionally when connected to a gaming laptop. Compatabilty issue?

Dec 18, 2019
The Laptop:
Asus ROG Strix SCAR III G531GW-AZ051T
OS: Windows 10 Home 64Bit
CPU: Intel® Core™ i7-9750H Six Core Processor, 12M Cache, 2.60 GHz up to 4.50 GHz
RAM: 32GB (2x16GB) DDR4 2666 MHz SDRAM, 2 x SO-DIMM socket for expansion up to 32GB SDRAM
Memeory: 1TB 5400RPM SATA 2.5 Inch Hybrid HDD (FireCuda) + 512GB M.2 SSD NVMe™ PCIe®
Monitor: 15.6 Inch Full HD (1920x1080) IPS-level panel, 240Hz, 3ms, 100% sRGB, 300nits

The Monitor:
Asus MX27UC 27'' LED 4K AH-IPS
Resolution: 3840x2160
Response Time: 5 ms
Inputs/outputs: HDMI, DisplayPort, DisplayPort over USB-C, USB 3.1x2
Power: Power On <35W*, Power Saving <0.5W, Power Off <0.5W, Voltage : 100-240V, 50/60Hz

They are both brand new.

The Problem:

I was planning to game on the laptop (which has a 240Hz screen) and take it to work to show my designs,
while having a 4k monitor (60Hz) at home for content creation/browsing/movies.
When I connect these two, everything seems fine for anywhere between 2 minutes and 2 hours. Then the screen crashes and looks like this:

The glitch colors change depending on what I was viewing at the time. It's completely random, while doing nothing particular.
This only happens to the 4k monitor. The laptop itself is unaffected by this and I can still use the main screen while the external one is stuck like this.
To fix the problem, I simply turn the 4k monitor off and on. Then wait for the next time it happens...

This is very annoying and my life is in ruin. I don't know why it occurs. However, I think it's somehow related to the GPU.
Here are some of the things I tried that might help narrow down the issue:

Things that work:
The gaming laptop works perfectly fine with my old full HD Dell monitor.
The 4k monitor works perfectly fine with my old PC from 7 years ago.

Things that don't work:
Re-adjusting the cables and making sure they are connected properly
Using different outputs and cables. I tried 2 different HDMI cables and a USB-C cable.
Updating drivers as well as reverting to old drivers.
Changing between different display resolutions.
Changing 'projection' options (secondary/main/both)
Turning off anti-virus.
Disabling / enabling the monitor's speakers.
Disabling hardware acceleration.

The insurance only covers hardware malfunction, so I can't really do anything about it
as both the laptop and the screen work fine on their own and with different hardware.
They only have a problem with each other.

Please help me figure this out :(