Using PCIe to M.2 board for RPi5 (WaveShare), and M.2 to standard PCIe adaptor board for the card.
JTAG connected as usual, and a external 12V jack is soldered on the board.
I'm using 12V 3A power supply, it's enough for small designs but may not be so for larger designs.
12V 1A certainly doesn't work.