No, I'm looking for an app which will be secure, as in, lack backdoors or obvious security issues. I understand that OS can compromise it, but I more or less tr

No, I'm looking for an app which will be secure, as in, lack backdoors or obvious security issues. I understand that OS can compromise it, but I more or less trust my normal OS, and it seems weird to use a "secured" OS, because that's where I'd expect all the backdoors to be. Not to mention the fact that if your threat vector is "Apple looking through you photos", you probably don't even need anything special in the first place - popular Linux disto with some Matrix client will be just fine.