The current wisdom is to have specific tools/constructions for specific purposes, so as to eliminate/reduce footguns and to incorporate modern cryptography.
At a lunch for female journalists and scientists, Hunt gave a speech...
"It's strange that such a chauvinist monster like me has been asked to speak to women scientists. Let me tell you about my trouble with girls. Three things happen when they are in the lab: you fall in love with them, they fall in love with you, and when you criticise them they cry. Perhaps we should make separate labs for boys and girls? Now, seriously, I'm impressed by the economic development of Korea. And women scientists played, without a doubt, an important role in it. Science needs women, and you should do science, despite all the obstacles, and despite monsters like me."
It seems the answer is Brian Warner's magic-wormhole. You're gonna see lots of file transfer sites with wormhole in their name, but if you want security you should use the original one, which is BW's m-w.
It is implemented in Python [1], so it's hard to install.
So someone made a Go version of it [2] that has binaries for windows, Mac, Linux, BSD etc. But it's command line so maybe not suitable for lay people.
So another person made a GUI for it that also has binaries for all OS [3].
Also there is an android app [4]. Someone needs to implement an iOS one.