I'm replying very late but I had to do a lot of tests and to be sure.
Actually, after a lot of re-installations of Armbian on my Odroid C2, it seems now it's working without hanging up.
It's been 2 weeks without the need to power cycle.
I installed Armbian on SD card, then moved installation on eMMC with armbian-config, then formatted the SD card and now I'm using that as docker root, in fact I'm running pi hole and emby (switched to it from plex) as docker containers.
If it's keep on being stable, I won't change it. Even if I don't know why it was so unstable.
Thanks for all the advices.