I changed from .emacs to .emacs.d/init.el when it became possible, because that seems neater. Some years later I decided to see what fancy packages the young folks like, and started using vertico, orderless, marginalia, embark, and consult. I'm still going to reserve judgment on embark and consult, but at least the first three packages are certainly great additions.

My point is: the api of of emacs is fairly stable. And your point is?

I have ~80 lines outside the customize variable block added by emacs. Nothing too fancy but there are a few hot keys and functions that I can't live without.