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)))

Doesn't work for me:

Debugger entered--Lisp error: (args-out-of-range 1064 1065)
  add-text-properties(1064 1065 (gnus-group "nnrss:Richard Stallman" gnus-unread t gnus-marked 32 gnus-indentation "" gnus-level 3))
  gnus-group-insert-group-line("nnrss:Richard Stallman" 3 nil t (nnrss ""))
  gnus-group-insert-group-line-info("nnrss:Richard Stallman")
  gnus-group-make-group("Richard Stallman" (nnrss ""))
  (if (gethash (gnus-group-prefixed-name title "nnrss") gnus-newsrc-hashtb) nil (gnus-group-make-group title '(nnrss "")) (setq nnrss-group-alist (cons (list title href desc) nnrss-group-alist)) (message "Group %s added" title) (nnrss-save-server-data nil))
  (let* ((title (nth 0 feed)) (href (nth 1 feed)) (desc (nth 2 feed)) (coding (gnus-group-name-charset '(nnrss "") title))) (if coding (progn (setq title (decode-coding-string (encode-coding-string title coding) coding)))) (if (gethash (gnus-group-prefixed-name title "nnrss") gnus-newsrc-hashtb) nil (gnus-group-make-group title '(nnrss "")) (setq nnrss-group-alist (cons (list title href desc) nnrss-group-alist)) (message "Group %s added" title) (nnrss-save-server-data nil)))
  (let ((feed (car tail))) (let* ((title (nth 0 feed)) (href (nth 1 feed)) (desc (nth 2 feed)) (coding (gnus-group-name-charset '(nnrss "") title))) (if coding (progn (setq title (decode-coding-string (encode-coding-string title coding) coding)))) (if (gethash (gnus-group-prefixed-name title "nnrss") gnus-newsrc-hashtb) nil (gnus-group-make-group title '(nnrss "")) (setq nnrss-group-alist (cons (list title href desc) nnrss-group-alist)) (message "Group %s added" title) (nnrss-save-server-data nil))) (setq tail (cdr tail)))
  (while tail (let ((feed (car tail))) (let* ((title (nth 0 feed)) (href (nth 1 feed)) (desc (nth 2 feed)) (coding (gnus-group-name-charset '(nnrss "") title))) (if coding (progn (setq title (decode-coding-string (encode-coding-string title coding) coding)))) (if (gethash (gnus-group-prefixed-name title "nnrss") gnus-newsrc-hashtb) nil (gnus-group-make-group title '(nnrss "")) (setq nnrss-group-alist (cons (list title href desc) nnrss-group-alist)) (message "Group %s added" title) (nnrss-save-server-data nil))) (setq tail (cdr tail))))
  (let ((tail feeds)) (while tail (let ((feed (car tail))) (let* ((title (nth 0 feed)) (href (nth 1 feed)) (desc (nth 2 feed)) (coding (gnus-group-name-charset '... title))) (if coding (progn (setq title (decode-coding-string ... coding)))) (if (gethash (gnus-group-prefixed-name title "nnrss") gnus-newsrc-hashtb) nil (gnus-group-make-group title '(nnrss "")) (setq nnrss-group-alist (cons (list title href desc) nnrss-group-alist)) (message "Group %s added" title) (nnrss-save-server-data nil))) (setq tail (cdr tail)))))
  my-subscribe-rss-feeds((("Richard Stallman" "https://stallman.org/rss/rss.xml" "Chief GNUisance of the GNU Project")))
  (lambda nil (my-subscribe-rss-feeds my-feeds))()
  run-hooks(gnus-setup-news-hook)
  apply(run-hooks gnus-setup-news-hook)
  gnus-run-hooks(gnus-setup-news-hook)
  #f(compiled-function () #<bytecode 0xff7750be0821785>)()
  gnus-1(nil nil nil)
  gnus(nil)
  funcall-interactively(gnus nil)
  call-interactively(gnus record nil)
  command-execute(gnus record)
  execute-extended-command(nil "gnus" "gnus")
  funcall-interactively(execute-extended-command nil "gnus" "gnus")
  call-interactively(execute-extended-command nil nil)
  command-execute(execute-extended-command)

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?