Somewhat off topic: There are PCIe to PCI slot adapters. IMO avoid ones with ASMedia bridge chip and prefer ones with PLX or Tundra bridge chip.This card is PCI, not express... Any chance ? […] NO EPYC board has any PCI slots, all PCI Express x16 or X8 or X4.
(Whether or not it is possible to boot from media which are attached via a PCIe or PCI based controller is then another question. Depends on presence of an option ROM on the controller, and the mentioned UEFI/dual/legacy mode switch in the BIOS.)