It irks me that some people use this term to mean "doing your job, as expected." I would imagine it to mean "doing the absolute smallest amount you can get away with without getting noticed and subsequently fired." Fulfilling my duties but not doing overtime seems like "doing your job" rather than "quiet quitting."
I think it's an indication of a totally dysfunctional work culture that "not doing extra" can be synonymous with "not working at all"
The fact that the author claims to have given "200% of [their] energy" to their job "throughout their career" is, to me, depressing rather than admirable