Just because the protocol has flaws, doesn't mean everyone can exploit them.

On the other hand it's possible for Google to read every communication because they have root on your phone. So using Telegram [1] with a custom ROM without Google services (e. g. [2]) will make it harder for Google at least. Not easily possible with Signal.

[1] https://f-droid.org/repository/browse/?fdfilter=telegram&fdi... [2] https://copperhead.co/android/