Dell Precision 3630 Tower with an RX 5700xt Dell Oem (038MPY) and crashes a lot

Unit Specs:

CPU:Intel i5 9500

RAM: 16gb 2400mhz single channel, SK Hynix

PSU: Corsair RM750

BIOS: Latest one

Chipset: Intel c246

I have an DELL OEM rx 5700xt (038MPY)  for my Dell Precision 3630 and constantly green screen in windows in load or after a "deload" like leaving a benchmark or finishing one, i have an Corsair Rm750 as an psu which should be more than enough. I've tried various fixes like disableing mpo, dwm in windows, disabling c states and aspm in bios, i've tried to swicth the pcie link speed to pcie 3 but i only have auto, pcie 2 and pcie 1, i switched hdmi cables and monitors and my card weirdly crashes in the bios and in windows 11 safe mode, i have an idea that this might be a cpu issue but i got my unit from an reputable refurbeshing company in Romania (citgrup.ro), it supplies gouverment ran institutions so i highly dought thats it is the cpus/mbs fault. In bios it just randomly crashes into a black screen, in safe mode it artefacts and crashes, in windows it crashes under a few seconds in full load (3d mark, amd adrelalin stress test, unigine superstition and unigine heaven, same behaviour). Card has been repasted, cpu reseated, gpu reseat in numeorous times, i've also tested with a gt 730 (fermi, gigabyte version) and never crashed. Bios is the lastest, chipset drivers are the lastet... Same behaviour when running it through iGPU expect that the image just gets stuck at the lastest frame. I'm completely lost my only thought is to flash another gpu bios...