OP here. I built this after Google Drive sync silently wiped my local files and the deletion propagated to the cloud instantly.

CloudChute is a native macOS app (Swift, not Electron) that turns your existing Google Drive into a proper, one-way backup vault.

It encrypts data locally and stores it in the restricted appDataFolder—so your backups are isolated from your main Drive view and safe from sync errors. No tracking/analytics, just a maintenance fee for the client.