Maybe it is interchangeable sometimes, but English people would rather point at the UK, while Anglo-Saxons often abusively refers to UK plus majorly white former British colonies, USA, Canada, Australia and New-Zealand.
Interesting. I’d probably call that “the anglosphere”, Anglo-Saxon is specifically the pre-Norman-conquest residents of what is now England.
Wouldn’t the Anglosphere include every English speaking countries like South Africa, India and others?