Signal is the best. End-to-end encryption and the ability to configure disappearing messages. It used to be that Android phones could set Signal as the default SMS app, but no more, as a safety feature. It was nice to use Signal as the standard messaging service on your phone, which did not require the other user to have Signal installed. But that is changing, so both sides need to install Signal.
“and the ability to configure disappearing messages.”
Nice, it seems that might encourage some more timid members to post something they aren’t certain about.