Do I understand that right that you've had issues with your Docker(s) when using the path /mnt/disks/whatever?
I now run basically everything from ZFS (mounted to /mnt/nvme), my Docker path for the Docker images, libvirt image, appdata, domains, system,... and had never had a single issue with it.
@steini84 also told me now that multiple people report they have issues doing it this way but I don't haven't got a single issue so far.
I think since this is a plugin that extends Unraid in it's functions there is no right or even wrong way to do it.
It's always up to the user where you set your mount points for ZFS and from my perspective if it works for you, then leave it as it is...