xkcd.com/1782/

Matrix, XMPP, etc. will all pass and be forgotten.

IRC will never die, and the channels on it are often useful. I suggest starting with libera.chat

Find a client you like. I’m on Mac, I tolerate LimeChat, Adium is “better” but I don’t use any other chats, which is what it’s for. There’s plenty of options. ircii is the classic.