I realize I've missed a lot.
Someone should write an Emacs guide for people who haven't meaningfully touched their .emacs since the early 2000s
The bulk of the Mastering Emacs blog is a decade old at this point, but its philosophy and the information it provides is still very relevant for any graybeard wanting to get up to date.
There's a lot of Emacs information on the internet, and your agent has been trained on it.
It’s already built in! C-h n view-emacs-news