If you like this, I'd highly recommend the book, "Shady Characters: The Secret Life of Punctuation, Symbols, and Other Typographical Marks": https://a.co/d/iqGNnyi
Not on punctuation specifically but otherwise highly recommended Robert Bringhurst's "The Elements of Typographic Style" discusses the ampersand and its usage in great depth. Somehow Bringhurst's obsession with this character is almost uncanny.
I'm getting The Da Vinci Code vibes.
As in you think it’s a load of curious but bullshit stories?