Yes, you have one month time to switch and then on the first sunday of the next month you should talk about your switch with someone or post it somewhere. That’s the idea of #DIDit.

I don’t use messengers with vendor lock-in. Therefore Matrix and XMPP see: https://www.messenger-matrix.de/messenger-matrix-en.html

Both self hosted on a Raspberry #freedombox https://freedombox.org/

Matrix has all the features like Slack and WhatsApp and XMPP Conversations: the very last word in instant messaging.