Question Gigabyte Z390 Auros Elite Cooling

[RudeboyJohn]

Morning folks. So, brand new to owning a custom gaming rig. I bought it pre-buitl from CUK, the Mantis tower. Liquid cooled with an Asetek 550LC Gen4 120mm AIO CPU Liquid closed-loop. TWO months later, the entire PC shuts down from overheating (I can feel the heat just above the vent over the motherboard. There are 6 highpowered fans and the vents are all cleared and pristine, all fans operating. Any suggestions on how to fix this? Could it be a faulty heatsink? I can hear the liquid pump every now and then.
Opened up the glass case and checked the card itself is the only thing that feels hot.
Stats:
DT-CU-0035-CUK-087 Mantis Custom Gaming PC Liquid Cooled Intel i7-9700KF
32GB Ram
1TB NVMe SSD + 2TB HDD
Nvidia GeForce RTX 2070
600W Gold PSU
Windows 10
____
MB-GB-0027 Gigabyte Z390 AUROS Elite motherboard
AC-H20-0045 Asetek 550LC Gen4 120mm AIO CPU Liquid Cooler
AC-GPU-239 NVIDIA GeForce RTX 2070 8GB GDDR6 Graphics Card
AC-PS-0900 Thermaltake SMART 600W Gold PSU

 

[RudeboyJohn]

Update and more info: Installed Open Hardware monitoring so I can see the spikes of temps.
CPU (which is liquid cooled) whispers at a steady 30-40 C temp when running GFX intensive games.
GPU spikes from idling 30 C quickly to 70-80 C, prolonged operation at that temp shuts it off.
--GPU fans operating at 1200-1800x RPMS steadily, with perfomance at 80%.

So...bad heat sink on the GFX itself?

Should I invest in a GPU cooler mod, like Kraken/CoolMaster etc? If so, which is compatible with the GFX stats above?

I'm aware that I could clip/drill NZT cooler brackets to modify it to fit on the card and not rub up against components, but obviously, REEEEALLLY don't want to do that. Rather have a cooler I can mount and plug-in-play to the motherboard.

Any tips on installing a GPU dedicated cooler system for a vertically mounted tower setup? Looks like I have plenty of overhead space.

UPDATE: Custom set my Fan curves to help mitigate cooling at higher ramp speeds. Underclocking and pulling back the max temp/power limit (using Afterburner). Helps to maintain the GPU temp around 72-73C...which holds for at least 30mins of gaming perfomance.
Still uncomfortable with the heat output. The glass side paneling is hot to the touch, and the top vents are putting out hot air.
I figured my air flow would be great with this chasis, but I guess not.

So, I guess I'm at the point where I should go ahead and invest in a GPU cooling system. So, any thoughts?