Armbian and DietPi as as much Debian as the Radxa Debian image 
. What you use and what of course is expected to work is that vendor’s (Radxa’s) kernel and bootloader, which is the key difference.
The problem is that this kernel is ancient, and has hence issues and limitations on recent Debian versions, regarding container engines and modern kernel features like WireGuard, nftables/bpfilter and more, and a set of additional problems with Bookworm, the next Debian release this summer. This is also the reason why Radxa is providing Debian Buster (EOL since last summer) images only. And as vendors usually never update their kernels for one device, it has no future.
the 2nd option with Armbian doesn’t really work either
Can you go into detail why exactly did not work, where it failed, in case error messages? This is actually supposed to work reliable, as long as the Armbian image itself boots. And you did select “22: Generic device” in the installer? Selecting “ROCK Pi 4” would break it.
It seems to work fine on SD card, btw, so indeed only eMMC support is missing with the U-Boot build: Rock4C+ no-wifi-hardware-found