@shrimpney @connynasch @mgeist You could use email which is also used by 99% of the internet population. There are multiple ways to add Signal like encryption to it. Make sure you have (or made) a server that has all the security updates though: https://bookofadamz.com/how-to-tell-if-your-email-service-sucks/
@Adam @shrimpney @connynasch @mgeist 99% of the regular user email population (I'd honestly suspect closer to 100% than 99%, globally for individuals) are not using an email service that even has built-in support for those encryption tools, let alone have all of the features enabled and correctly configured. The list of checks on that site do not look at all user-friendly or approachable for the average person to figure out.
If you send messages you think are going to be encrypted but they are received by a system that scans them anyways and puts that in a big tech database on the recipient's end, that is strictly worse than a system where you can have relative confidence that any message you send will have adequate encryption by default.
A system that *can* be secure if you do things just right, and so does your sender is not actually a particularly secure system.
