I can confirm that the Odroid H4 Plus also supports in-band ECC. If I remember right, Memtest86 showed different stats when I ran it with in-band ECC enabled/disabled though I didn't have a good way to test that an error was actually corrected.
Only when they expose this feature in Linux EDAC drivers it becomes possible to do this. In the past Intel had maintained well its Linux EDAC drivers, but AMD had frequently great delays between the launch of a CPU and the update of the drivers. After the many lay-offs at Intel, it is unknown whether in the future their Linux support will remain as good as in the past.