The FAQ is written for my community builds, I am unable to track changes other developers make in their builds.
"nand" device tree was designed for devices with NAND chip in meaning "not eMMC" and you should only use it if internal memory of your box is not detected. This is actually covered in FAQ.
Okay thx nontheless the 'not eMMC dtb' (which is true for beelink) always worked till 8.90.4.