I liked Discord's solution of chosen name + short identifier, although I might have changed 4 numbers to 5 base64 digits, because no matter what the username, o

I liked Discord's solution of chosen name + short identifier, although I might have changed 4 numbers to 5 base64 digits, because no matter what the username, over a billion people trying to use the same name is unlikely, and 5 base64 digits can still be shared easily.