not to shit on you specifically but I see this over and over, folks asking how to be "secure". secure against what?

if you're into this, you need to set up a "threat model" i.e. what are your threat vectors and then you build your defenses against that model. a defense against blanket surveillance doesn't handle targeted threats. a successful defense against your government doesn't preclude other nation-state actors getting at you.

like, if your threat vector is e.g. your SO "inspecting" your phone, you set up a passcode and you're safe against that threat. but, if there's a toddler going around smashing stuff, your defense isn't valid. defense against that vector is placing your phone high up. but that defense isn't effective against SO.

I am sure any messenger recommended here can be successfully red-teamed, be it design flaws, operator error, the famous wrench comic, or whathaveyou. but that doesn't mean it's ineffective in your specific case.