So I'm in a somewhat unfortunate situation. My circle of friends doesn't want to switch to another messenger and we are currently stuck on the worst possible platform for security: Telegram.
The problem is that it is very hard to convince anyone to switch, if they are all perfectly fine and like Telegram. I mean I can get why they like it: The UX and UI of Telegram are amazing and there are well functioning clients available for any platform. It has more features and gimmicks than any other messenger I know BUT it lacks one mayor thing: E2EE. And that's mostly what I care about. The second problem is that I was the person who recommended the switch to Telegram right after WhatsApp was bought by Facebook. I know, that was a bad recommendation, but back then I didn't know shit about privacy or why E2EE mattered. I was just like "Hey, it's not by Facebook, so it must be better". And now everyone I know is there and won't leave.
If - in the hypothetical situation of me setting an ultimatum and deleting my Telegram after that - I wanted to make them switch somewhere else: What messenger would that be? Currently I'm mostly thinking Signal. I know it's not perfect either, it is centralized, and the servers are in the US, but it has a bigger user base already than most of its competitors like Threema or Matrix/Element and it is very easy to set up and use. I'm already a user of Signal, Threema, Matrix, WhatsApp and Telegram (every platform for some contacts, but most of them on Telegram sadly), so having yet another option is not a problem for me, as well as getting rid of one is also no problem. I'd love to delete both Telegram and WhatsApp in this move.
So, in conclusion, what I need is a messenger that has all or most of the following:
- best possible security (E2EE is minimum)
- easy to use (no complicated setup, simple UI)
- already has some users (not too niche)
- cross-platform and multi-device (should run on Android, iOS and Windows/Web)
- some flashy dumb features like stickers and so on to keep them entertained
My choice would be Signal. But I am unsure if that is the best choice or if I should just wait a bit and see what all of the new EU laws about messengers and gatekeepers bring to the game and if anything chances with that.
DMA will only affect Whatsapp and Facebook Messenger from messengers, Apple's iMessage manage to be excuded as they don't have 45 million active users (10% of EU population).
Edit: I said Google Messenger when I meant Facebook.
Signal fits all of your criteria.