Your said you were going to use the cloud services, so even if you self-host, using a cloud service api carries the same risk as using their apps. This is an app to unify all the remote storage things.
However, after looking at the code, I retract my comment and caution you not to use Drivebase:
[crypto]
# Generate: openssl rand -base64 32
masterKeyBase64 = "<base64-encoded-32-byte-key>"
If this is a salt or a seed, the documentation is wrong. But it looks like they're using this base64 value as the actual key for whatever encryption Claude has vibe-coded into it.
base64 values can be reversed very trivially.
Don't use this.