Call me on my free email or my nostr pub key via 0xChat

Matrix, XMPP, SIP, Teams™ (proprietary), Google (proprietary), SSB radio, etc, etc, etc. I recommend XMPP for lightweight server with minimal state, or Matrix which has server side logging (and extensive server side state that entails). Both of these are easily bridged to telco for your friends in 20th century countries.

Nostr pub key man.. nostr pub keys...

nobody gonna memorize a nostr pubkey, and virtually no nostr clients support contacts and labeling