Which Rock Pi board do you have? There is a version 1.3 model which has solder pads for a chip to enable booting from other than SD card or EMMC chip, but there is no chip installed. Version 1.4 has the chip installed. See:
https://wiki.radxa.com/Rockpi4/hardware/spi_flash
If you’ve got the version 1.3 model you can buy one and solder it in if you’re brave enough. I did that and was able to get thing operational. But if you have the version 1.3 board and don’t add the spi flash, it’s not possible to boot from an nvme drive.