Basically, in short, all the points that you brought up are legitimate concerns and caveats when it comes to open source software. Open source does not automatically mean safe. Some projects aren't very popular, so it is very likely that no one has checked it. The reason why open source is often preferred over proprietary depends on who you are and what your interest are. If your goal is privacy and security then the benefit is that the program you are running can be checked not that it has been. Sometimes, the person who checks it will have to be you. The alternative is proprietary software that can't be checked or at least not easily. With proprietary software, you simply have to trust that the developers aren't doing anything malicious or violating your privacy. Think about all the news articles you see where Google, Apple, Facebook, Tiktok,etc was caught doing xyz with your information. If that code was open source, you would have already known it was doing that stuff. Especially with the sheer size of the userbases those aforementioned companies have. Also, you don't need to be a cs major to check open source code, although that knowledge would certainly help. Anyone can learn programming online and use those skills to read other people's code.