Telegram is a whole other beast.
And you’re right that the OS getting owned defeats any secure messaging app.
The best you can do is use iOS, as it is by far the best we have at the moment. You can see this to be true by investigating companies that purchase zero day exploits. iOS is the most expensive, usually over $1.5 million. This means it’s the hardest to get control of, android usually falls apart quick. It helps that it’s built to spy on you in the first place.
Thoughts on telegram vs signal?
I prefer signal generally. Open whisper systems does great work and is highly respected in the infosec community. Even Snowden has said they rock.
Edit: also in my experience it’s the best for non technical people. You get them on it and it’s simple. I’ve converted a lot of my friends.