I just tested this again with the latest Debian CLI Bullseye_Legacy build from December 9th. I can boot from the SD card fine. Rock 5 running stock radxa 30W power supply. Ran fdisk on my WD Black SSD, deleted all partitions, the created just one using mkfs.ext4 /dev/nvme0n1p1. Once complete, I ran armbian-install and installed on to /dev/nvme0n1p1, and then flashed the SPI when prompted. Once complete. I selected power off when prompted, then unplugged the power and removed the SD card. I powered the Rock 5 back on, and the activity LED has been solid green-blue ever since.
If I boot to the SD card, but power it down, inserting the SD card, then powering it back on. It's solid green-blue for 5 seconds before it drops to just green with a double blink of the blue LED once a second.
I've installed the radxa Rock 5 image on the NVME, and loaded up the SPI and that boots fine, but for some reason, I can't get it to boot on Armbian.
I also tried flashing the NVME directly with BalenaEtcher with the same image, then initially booting with an SD card to run armbian-install to install the SPI. Same thing, when it boots, the activity LED is just solid green-blue. I think I let it run for 30 minutes at one point with no change.