In a centralized management scenario, the central controlling service needs the ability to control everything registered with it. So, if the central controlling service is compromised, it is very likely that everything it controlled is also compromised. There are ways to mitigate this at the application level, like role-based and group-based access controls. But, if the service itself is compromised rather than an individual’s credentials, then the application protections can likely all be bypassed. You can mitigate this a bit by giving each tenant their own deployment of the controlling service, with network isolation between tenants. But, even that is still not fool-proof.
Fundamentally, security is not solved by one golden thing. You need layers of protection. If one layer is compromised, others are hopefully still safe.
In general, container root filesystems and the images backing them will not function on NFS. When deploying containers, you should be mounting data volumes into the containers rather than storing things on the container root filesystems. Hopefully you are already doing that, otherwise you’re going to need to manually copy data out of the containers. Personally, if all you’re talking about is 32 gigs max, I would just stop all of the containers, copy everything to the new NFS locations, and then re-create the containers to point at the new NFS locations.
All this said though, some applications really don’t like their data stored on NFS. I know Plex really doesn’t function well when it’s database is on NFS. But, the Plex media directories are fine to host from NFS.