Gnus RSS config

.gnus.el

(setq my-feeds '(("Richard Stallman" "https://stallman.org/rss/rss.xml" "Chief GNUisance of the GNU Project")
                ;; Define other feeds right here (title url description)
		 ))

;; This function mimics `gnus-group-make-rss-group' behaviour
(defun my-subscribe-rss-feeds (feeds)
  (require 'nnrss)
  (dolist (feed feeds)
    (let* ((title (nth 0 feed))
	   (href (nth 1 feed))
	   (desc (nth 2 feed))
	   (coding (gnus-group-name-charset '(nnrss "") title)))
      (when coding
	;; Unify non-ASCII text.
	(setq title (decode-coding-string
		     (encode-coding-string title coding)
		     coding)))
      (unless (gnus-group-entry (gnus-group-prefixed-name title "nnrss"))
	(gnus-group-make-group title '(nnrss ""))
	(push (list title href desc) nnrss-group-alist)
	(message "Group %s added" title)
	(nnrss-save-server-data nil)))))

(add-hook 'gnus-setup-news-hook (lambda () (my-subscribe-rss-feeds my-feeds)))

I’ve tested that just now and it still works fine. Which emacs version are you using? Also, can you please start with emacs -Q so we can rule out errors due to customizations?