People can change fairly quickly to a new platform and it doesn't have to be all or nothing. I stopped using WhatsApp and have convinced most of my friends to install Signal for communicating with me in place of SMS.
However it's hard to recommend because of the lack of features.
...and which most of my friends used.
I'm OK with Signal's UX, but the problem is that I know exactly two people who use it too, everyone else is on WhatsApp. I mean: Writing this implementation would be hard, but still tremendously easier than getting enough traction to make it useful.