

No. This isn’t a thing. Don’t try to make it a thing.
Once something leaves your computer you lose control of it. The recipient can do whatever they want with the message. If you don’t trust the recipient not to be malicious then don’t send them anything sensitive. You can’t untell a secret.
I think F-droid is woefully misunderstood especially in privacy circles.
The main benefit of F-Droid is that it works (as best it can) to guarantee software freedom. This means, for each app, you can be assured it is under a free software license, built from corresponding source code, and contains no proprietary components. F-droid has an inclusion policy that forbids proprietary blobs and they have to build everything from source in order to ensure that - however, if the app is reproducible, F-droid can actually verify that the already built app from the developer satisfies the inclusion policy without needing to sign its own builds, which is ideal. It’s important to note that without building from source, there is no way to guarantee that the source corresponds to the binary, which is important for exercising the four freedoms.
I don’t agree with everything F-droid does and I don’t think F-droid is perfect. The security folks have a few valid points, I think, but they fail to offer a solution that solves the same problem that F-droid does, either because they misunderstand what problem that is, or simply do not care about it. F-droid is not an app store, it’s a community-maintained distribution like a GNU/Linux distribution. App stores are not alternatives to F-droid and serve different problems. There is, as far as I know, no other project that attempts to serve the same purpose as F-droid.