RPi 3 to ASUS Tinker Board

Hello,

A dietpi-backup ?

Yes, it will simple not work. But you can easy test it. Nothing will get broken, it will simple not start up.

Aside from this, RPi based on “Rasbian” and Tinker Board on “TinkerOS” all based on “Debian” but with hadware specific closed source binary blobs in their special compiled kernels.
And ARM boards use different boot up sequence and routine, eg. Das U-Boot, because they have no BIOS or UEFI.