This is my emacs setup for AUCTEX with ConTeXt.

;; Install straight.el

(defvar bootstrap-version)

(let ((bootstrap-file

       (expand-file-name "straight/repos/straight.el/bootstrap.el" user-emacs-directory))

      (bootstrap-version 5))

  (unless (file-exists-p bootstrap-file)

    (with-current-buffer

        (url-retrieve-synchronously

         "https://raw.githubusercontent.com/raxod502/straight.el/develop/install.el"

         'silent 'inhibit-cookies)

      (goto-char (point-max))

      (eval-print-last-sexp)))

  (load bootstrap-file nil 'nomessage))

;; Install use-package

(straight-use-package 'use-package)

;; Configure use-package to use straight.el by default

(use-package straight

             :custom (straight-use-package-by-default t))

(use-package yasnippet)

;;; Auctex

(defun my-context-setup ()

  (custom-set-variables

   '(ConTeXt-Mark-version "LMTX")

   '(ConTeXt-engine "lutametatex")))

(straight-use-package 'auctex)

(add-hook 'ConTeXt-mode-hook

                  (lambda ()

                    (reftex-mode 1)

            (flyspell-mode 1)

                    (auto-fill-mode 1)

                    ;(relative-line-numbers-mode 1)

                    ;(abbrev-mode 1)

                    (my-context-setup)

                    (yas-minor-mode)

                    (yas-reload-all)))

I hope this help you

Mauricio