What GPU are you using? If have 12VHPWR socket can use the native 12V 2X6 connection instead.

If your only choice is those 2 then your answer is Leadex iii since Vita GM ady not compatible with 2 PCIE connect. You could take the risk of using the pigtail on the Vita GM but thats at your own risk to find out if if works.

Otherwise like above said, sell it and buy some other.

BTW what happen to your Hydro G Pro?

FSP is a reliable OEM brand, my HV Pro been running since 2022 til now, but I guess things happen and maybe theres other factors as high end PSU have lotsa protection b4 it can blow. Was the PC connected to a UPS or AVR?

I can fully trust FSP. I still have FSP Hexa 500W still going strong on low power rig. Using FSP Hydro Ti Pro 1000W on my main rig.

All brands, even good ones can have faulty units.  My Cooler Master V650 V2 which was a Tier A+ unit ended up faulty within 1 month of use
Eventually the retailer did a full refund