NB Just to be clear, I'm not doubting you, but if I was in a situation where my life or liberty was at threat I would be very worried about whose advice to take.
If you are not so technical then you have to decide who to trust. For example, you may trust that open source software has been vetted enough and build one from source. Or trust that the built artefacts downloaded from github is good enough. Or trust that the software downloaded from a website not marked as fraud by Google Chrome is good enough. Etc.
In any case, the more technical knowledge you have, the more confidence you can have by doing due diligence yourself.
Every single thing the person wrote about is a protocol. Each has been written about extensively and they’re open source. You can read source code if you’d like.
Those are the best guarantees you can get with any software. If you’re not technical and not willing to do the research and put in the work, there’s nothing you can do.