I'm surprised master/slave's the hill you want to die on - it's the one instance where the old terminology really is just bizarre jargon that's being replaced with words that are a direct, common-language description of what they do.
I genuinely don't know because this aspect of English newspeak hasn't made it to my country yet.
Whenever any work-environment friction will arise, I'll stop using those words for sure, I value my job more than I value terminology.