i did a prune on non used docker images and it cleaned up some space. also i’ve migrated all the apps files (appdata folder) using the system, to my RAID and so far no trouble.
to prune the non used docker images you will need to access the system terminal or via ssh (not my case)
the you will need to login and enter the following command
docker image prune -a
WARNING! This will remove all images without at least one container associated to them.
Are you sure you want to continue? [y/N] y