The only truly secure communication will ever be in person with no possible recording devices present. Shit's pretty fucked for us.
private meetings in the nude then?
Honestly, yeah. And even then you have to consider location and pre-placed bugging equipment.
Remember that telegram, signal and most of the other privacy apps are all government funded silicon valley projects to circumvent other nations ability to manage information within their borders, its pretty safe to say that those services provide backdoors and firehose data feeds to the US government.
Dump the tech when protesting folks, or get burner phones and accounts which is expensive to do.
I can understand Signal since they've received massive funding by the US government, but how is Telegram a government-funded app?
Briar is an interesting example of how the thing could work: https://briarproject.org/how-it-works/