No local files should be able to be “tracked” by anyone unless you explicitly give the app permission. If you must give it permission, this is why “storage scopes” exist. You can create a folder exclusively for that app and give it access only to that folder.

If you’re trying to hide it from another user of your device, someone else already mentioned “private space”.

Private Space.

I think it’s a pretty new feature, but it seems to do what you want.

Use a phone that encrypts the user partition, which is any recent Android phone.

Also don’t enable file and storage permissions for any apps.

Cryptomator is pretty standard