Yes.

A. F-Droid only allows completely open souce stuff and informs you about things like whether it has privacy concerning features like trackers, relies on connecting to a closed source server, etc.

B. Obtainium doesn't give you any of those guarantees, but you can pull from a lot of different locations including .APKs from Microsoft GitHub releases, and

C. Aurora only allows you to get things listed on Google's play store (same backend)