FYI:
It was not a faulty Kindle! Partly out of stubbornness and partly out of sheer morbid curiosity, I decided to order another brand-new Kindle Paperwhite SE 2024 (with a Black Friday discount this time around

) and it behaves
exactly like my previous unit!
Has
anyone had any luck using Calibre on Mac OS with the new 2024 Kindles? Could it be my Calibre install that is somehow causing this???