Matrix isn’t ready for the general public and I’m doubtful it ever will be, so in the meantime Signal is the next best thing.

yeah, it is too complex etc. take a look at https://arcanechat.me/ and https://delta.chat/ (I contribute to these open source projects) they are probably the decentralized messengers that are more on pair with WhatsApp etc. super easy to use, no phone numbers or any private data required

Not me, but someone on the signal forums helpfully compiled many of them

thanks for sharing!