RockPi3a - No boot

Well first i wonder wich power pin ?
uart needs only rx ,tx and gnd and are female
outside usb connecters are gnd

well fancy booting of nvme doesnt help to check if a board works .

nvme and or sata boot requires 1 of that 3 below to work

! most of times it is a user mistake !

check wich device you want to boot from spi, emmc or sd

check the wiki wich jumpers has to be placed to boot from spi or emmc or sd

https://wiki.radxa.com/Rock3/hardware/3a

so to boot from sd check point 2.3 and 18 in the wiki

and if you still can’t boot a sd or any other device it still doesnt mean it is defect

so you have to try if bootrom aka mask-rom works
how to do that is explained here

if none of the above works you have a possibility it is defective but from the info you both provide it looks more a user mistake .