XMPP is used by many companies like Facebook , Google, Nintendo, GitHub, zoom, WhatsApp, Apple etc.

Facebook doesn’t use XMPP; they use a custom protocol built on top of MQTT. WhatsApp was using a binary equivalent to XMPP (keeping the same stanzas but removing the XML), but I’m not sure if they still are. Do you have a source stating that the other companies use XMPP?