Jeus man no ONLY use Signal, it;s the best and it;s the only one you need. We have court documents that show they don't keep any data on you and their crypto/app is all open-source and has been well peer reviewed. Available on iOS and Android so you can't go wrong.
There has been some bad news on Signal. But it's still recommendable.
There is one app which is better but I forgot the name.
It also depends on how secure the device used is in general.
Signal is Open Source - as in peer reviewed, checked and contributed to.
Anything that is proprietary,or closed ie Whatsapp, Wickr, Telegram, is open to backdoors and asking for trouble.
If Signal gets fucked over - the community will know about it.
There is one app which is better but I forgot the name.
It also depends on how secure the device used is in general.
All security depends on how secure the device is no matter what.