Not all etymologies are lies, words do have origins.
Just because you heard some stories which were false doesn’t mean all stories are false.
On this wiki page it is explained that linguistics do believe the word Yankee comes from Jan Kees or Jan Kaas. It explains it can also come from the name Janneke, which is a new to me.
I turned 38 today exactly, I checked al the boxes already, I’m prepared.