Before Karen became a proper thing, myself and my coworkers at my old retail job would call any Karen-like woman any boomer-esque name, I think we used Karen but also Diane, Susan, Janet June and Sharon amongst others for middle class 'Karens'. Working class Karen people were usually Pat, Liz, Magret, Debbie and Cathy.
A woman called Karen actually came in all the time who was actually a Karen. She would typically order stuff online, pick it up in store, try it on then have it refunded through the till. It would mess completely with our sales and footfall especially because if she wanted a different size or whatever she wouldn't exchange it in store and instead would try it on then reorder it online. If she did buy something in store, she would try and argue that it was faulty to get a discount. If we thanked her for pointing out the fault and offered her a fresh one from the stockroom she would refuse and order it online. We had an online ordering service in store which was relatively painless and gave you free delivery to any address (the website did not) but she always did it on her phone, right in front of us.
I knew het daughter from a uni society who was also total stuck up bitch and horrible to everyone who wasn't also a privately educated trust fund kid (she hid behind the quirky "Harry Potter fake nerd horse girl" persona). She used to boast about her daughter whilst looking down on me because I had to work. I recall once she made a snide comment about me working the weekend before exams and that she would never let her daughter work through university. Another time during summer she started to boast about how she paid for her daughter to go interrailling for two months.
Everyone else I know called Karen was/is absolutely fine and do not live up to their names at all.