Time to get off the mass surveillance grid. There are now multiple open source, point-to-point-encrypted, seriously evesdropping-resistant chatting options, most of them quite polished and easy to use.
This is a space that is rapidly expanding with multiple new entrants, and one or two recent entrants that are achieving some maturity.
Jabber is the granddaddy here, with the XMPP protocol almost as old as the e-mail (SMTP) protocol. OMEMO encryption is newer, but still very mature by this space's standards. ZERO OMEMO support for all Apple devices. Generally poor desktop support: though Gajim is functionally mature and works well on Linux and Windows desktops, it is a UI horror story. Jabber really shines on Android with the Conversations app, and shines even brighter because server-side is also open source, and not that terribly difficult to install and configure.
Also available on FDroid, delta.chat is very new, but in the bit of testing I have done with the Android client seems to work quite well. Delta.chat is one of multiple projects trying to make PGP-encrypted e-mail practical, and may be the first across the line. Note that it is a chatting, not an e-mail, solution, which should work with any of your IMAP-capable (at least Gmail and gmx.com) e-mail accounts, and is designed to not interfere with the normal working of your e-mail, they are separate activities in the same account. Desktop and Apple clients are also on the way, but I can not say how advanced.
Keybase starts to be a bit of an old-timer here, and this can be seen in the highly-polished UI and the (almost) flawless support across mobile and desktop, Linux, Apple, and Windows. EVERYTHING is ALWAYS encrypted in Keybase, so it is very difficult to make certain kinds of stupid mistakes that are common-place in, for example, PGP-encrypted e-mail. Key management is in a class by itself. There are some gotchas though. While Conversations and delta.chat above are very small efficient apps, Keybase is always and everywhere a resource pig. It will not run well on an old phone. It chews up a huge amount of disk space on desktops. Server-side there is also no sign that users will ever have the ability to run their own servers. Again, this is something one can [and I do] do with Conversations and delta.chat. Keybase also demands an e-mail address, but a throw-away will work since the e-mail is not necessary for continuing operation.
Matrix (whose main client on mobile and desktop browser is called "riot.im") is another up-and-comer like delta.chat, but much more ambitious. And seems to be struggling more, at least from where I am sitting. It offers multi-platform support client-side, and user-operable federated servers server-side, but encrypted messaging is currently too buggy for me to recommend Matrix, UNLESS you are looking for VoIP phone calls. None of the above apps have this, but Matrix does, and is worth keeping around just for that purpose even now. Matrix is going through an intense process right now of transitioning from beta to 1.0, and had the additional recent headache of an infrastructure hack. But there is a tremendous amount of community development energy going into the Matrix ecosystem, and I expect great things someday, and a usable network sometime quite soon.