Any modded app provided for free by some rabdom uploader is suspicious. You cannot blindly trust any platform. If you care about your privacy and your device’s security you should analyze the app’s content in depth or buy the app (or crack it yourself, but it usually means you need to buy the app first).

Longhorn is pretty easy to use. Garage works well too. Ceph is harder to use but provides both block and object storage (s3).

Did you read the first paragraph of the article?

Probably the training data.

Hmm, but in this case you would be recording either the ads or the buffering.