cannot get AUCTeX to work

[Pastiche P]

I just installed AUCTeX 13.0.1 using M-x list-packages. This is Emacs 27.1 under Windows.

I put this in my config:

(use-package tex
  :ensure auctex
  :config
  (setq TeX-auto-save t)
  (setq TeX-parse-self t))

Whenever I open a *.tex file, I get

Debugger entered--Lisp error: (void-function TeX-latex-mode)
  TeX-latex-mode()
  apply(TeX-latex-mode nil)
  latex-mode()
  funcall(latex-mode)
  TeX-tex-mode()
  apply(TeX-tex-mode nil)
  tex-mode()
  set-auto-mode-0(tex-mode nil)
  set-auto-mode()
  normal-mode(t)
  after-find-file(nil t)

I can't seem to find a similar error with Google, so I'm a bit at a loss.

If I put the setq statements outside of use-package, I can open the latex file, but I doubt AUCTeX has been loaded, because e.g. the command LaTeX-section is not defined...

Any pointers?

Thanks!