I need some good riser cable help, ive gone through 3 different sets of extension cables so far, and nothing will link at Gen4 speeds.

Linux/Ubuntu gives a bunch of hardware AER 'Data Link Layer Errors' at Gen 4 Links

But doing tests, they seem to work at full speed, it just fills up the event logs with those errors, ive tried different settings and disabling AER and nothing works. I disabled EVERY other device on the motherboard in case of conflicts. Updated BIOS, ensuring memory is on the supported list for the motherboard. Nothing is overclocked.

I have:
ASUS wrx80e-sage ii Mobo (Which has 7x PCIE 16x Gen 4 Slots)
Threadripper Pro 5955 CPU
128GB RAM
6x NVidia 3090 GPU's
2TB Samsung NVME

Mining Rig style case

Im trying to find good quality PCIE Gen 4+ Extension cables that are in lengths of 3@ \~7inches ,1@ 12 inches, 1@ 17" and 1@ 19"