In Australia, “Mate” Does Not Always Mean a Close Friend

In Australia, mate does not necessarily mean “a close friend”. It is also a common form of address for acquaintances and even people you have just met, often signalling equality and goodwill.

A shop assistant saying “Thanks, mate” is usually being casually friendly, not claiming a close relationship. Tone matters, though. A sharp “Listen, mate…” can sound warning or confrontational. With this word, relationship and delivery matter as much as the dictionary meaning.

https://history.cass.anu.edu.au/centres/andc/meanings-origins/all
https://researchportalplus.anu.edu.au/en/publications/mate-as-a-term-of-address-in-ordinary-interaction/