Nice tutorial.
I have got exactly same problem as squishykid, I followed his solution and it worked for me.
My hardware is:
RockPi 4C v1.2
ROCK PI 4X M.2 Extension board v1.6
ADATA SX8200 PRO 512GB (version based on SM2262ENG controller)
I used this build: Armbian_21.02.1_Rockpi-4c_focal_current_5.10.12.img
As I always was able to pass u-boot I think that my NVMe drive is compatible with RockPi.
Here is a picture of full error without squishykid's fix:
Here is a report generated by "armbianmonitor -u" from my installation: http://ix.io/2RsO
After applying squishykid's fix I was able to normally run the system (or maybe not - I only performed sysbench for CPU and NVMe on it).
But after running "apt get update && apt get upgrade && reboot" the system again won't boot up - I'm again getting the same error as in the picture above.
Here is a report just after doing "apt get update && apt get upgrade": http://ix.io/2Rtz
I don't know what has been broken by upgrade but the boot.cmd and armbianEnv.txt are left unchanged, also I created new boot.scr (by using mkimage) but still after upgrade I'm unable to boot again from my NVMe.