When the Snowden leaks started, I spent countless hours setting up PGP (GPG on Mac) email systems so that I could email with privacy. Since then services like Protonmail have sought to make it trivial. But nothing is easier than Signal or iMessage for that matter.
In fact I spend a lot of time lecturing family on sending me private things (like passwords, for some reason they send me passwords a lot) not in email, but in iMessage. I think to many that email feels far more private, but in reality it is the messaging platforms which are actually more private.