[SOLVED] Possible bad GPU, but no video from CPU either?

[neonplants]

Hey, I've been having tons of mysterious issues with my PC for over a year now.
I have a Gigabyte GeForce GTX 1650 SUPER 4 GB WINDFORCE OC Video Card installed.

My screen flickers on and off occasionally (monitor is fine), everything freezes every few days under almost no load, and the machine occasionally refuses to boot.
I've taken it to a competent repair tech, who says every single component passes every test he's got, but the issues I describe sound like a dying video card.
He told me to try and output video from my i9 CPU to see if everything worked normally without the GPU... but I'm getting no video at all from the CPU when I try.

I'm at a loss here - I've replaced every single component I have except for the GPU, and all parts are passing diagnositcs tests, and the thing still remains unusable.
Should I just get another graphics card and assume this is the issue? Any other ideas?
Thanks so much.

PCPartPicker Part List: https://pcpartpicker.com/list/tC8D9N

CPU: Intel Core i9-9900K (Standard Folding Box) 3.6 GHz 8-Core Processor ($354.99 @ Walmart)
CPU Cooler: Scythe Mugen 5 Rev. B 51.17 CFM CPU Cooler ($49.99 @ Amazon)
Motherboard: Gigabyte Z390 DESIGNARE ATX LGA1151 Motherboard
Memory: G.Skill Ripjaws V Series 32 GB (2 x 16 GB) DDR4-3200 CL16 Memory ($146.26)
Memory: G.Skill Ripjaws V Series 32 GB (2 x 16 GB) DDR4-3200 CL16 Memory ($134.99 @ Amazon)
Storage: PNY CS900 500 GB 2.5" Solid State Drive ($59.80)
Storage: Samsung 970 EVO Plus 2 TB M.2-2280 NVME Solid State Drive ($289.99 @ Amazon)
Storage: Seagate Barracuda Compute 2 TB 3.5" 7200RPM Internal Hard Drive ($55.49 @ Amazon)
Storage: Seagate BarraCuda Pro 10 TB 3.5" 7200RPM Internal Hard Drive ($349.00 @ Amazon)
Video Card: Gigabyte GeForce GTX 1650 SUPER 4 GB WINDFORCE OC Video Card ($173.99)
Case: NZXT H510i ATX Mid Tower Case ($106.99 @ Amazon)
Power Supply: Corsair RM (2019) 750 W 80+ Gold Certified Fully Modular ATX Power Supply ($124.99 @ Amazon)
Custom: Elgato Game Capture HD60 Pro, stream and record in 1080p60, superior low latency technology, H.264 hardware encoding, PCIe ($179.99 @ Amazon)
Custom: Elgato Cam Link Pro - PCIe Camera Capture Card, 4 HDMI inputs, 1080p60 Full HD, 4K30, Multiview, Streaming, Video conferencing, OBS, Zoom, etc. ($359.99 @ Amazon)
Total: $2386.46
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2021-08-16 18:21 EDT-0400

 

[punkncat]

Have you purchased a new video cable yet?
If the professional says it's all good, and you are absolutely sure the monitor is good that is about all that is left.

In some cases where you are using a GPU and iGPU you may have a setting in the BIOS to have that work together. I hope not "obviously", but have to plug into the motherboard output for that to work. In some cases you have to physically remove the GPU from the PCI slot.

Pretty much everything about your build seems a good pick. I am not 110% on board with the cooler along with a notoriously hot 9900K, but have seen people recommend it. Not really related directly IMO anyway.