I think that's a pretty odd concern to have. What would you imagine that looks like? If you're running these kinds of things securely, you should be locking down the network access to the hosts (they don't need outbound internet access, and they shouldn't need inbound access from anything except your application).
I think that worrying that a self-hosted file system has a backdoor to exfiltrate data is an odd concern. Security concerns are (obviously) normal, but you should not be exposing these kinds of services to the public internet (or giving them access to the public internet), eliminating the concern that it's giving your data away.