embark-org-column.el

  (defvar-keymap embark-org-column-map
    :doc "Keymap for Embark org-column actions."
    :parent embark-org-table-map
    "M-r" #'my-cua-enable-and-replace-in-rectangle-embark)

  (defun my-embark-org-column-at-point ()
    "Target the org-column at point."
    (when-let ((org-column
                (and (org-at-table-p)
                     (not (looking-at-p "|")) ; since then we don't know which column you mean
                     (let (beg
                           end)
                       (save-excursion
                         (let ((col (or (save-excursion
                                          (and (re-search-backward "|"
                                                                   (line-beginning-position)
                                                                   'noerror)
                                               (current-column)))
                                        (current-column))))
                           (while (org-at-table-p)
                             (move-to-column col)
                             (setq beg (point))
                             (forward-line -1))))
                       (save-excursion
                         (let ((col (or (save-excursion
                                          (and (re-search-forward "|"
                                                                  (line-end-position)
                                                                  'noerror)
                                               (1- (current-column))))
                                        (current-column))))
                           (while (org-at-table-p)
                             (move-to-column col)
                             (setq end (point))
                             (forward-line +1))))
                       (goto-char end)
                       (push-mark beg 'nomsg 'activate)
                       (rectangle-mark-mode)
                       (string-join (extract-rectangle beg end) "\n")))))
      (cons 'org-column org-column)))

  (add-to-list 'embark-target-finders #'my-embark-org-column-at-point)

  (add-to-list 'embark-keymap-alist '(org-column . embark-org-column-map))

  (defun my-cua-enable-and-replace-in-rectangle ()
    "Ensure CUA rectangle active, run replace in rectangle."
    (interactive)
    (unless cua--rectangle
      (unless cua--rectangle-initialized
        (cua--init-rectangles))
      (cua--activate-rectangle))
    (call-interactively #'cua-replace-in-rectangle))

  (add-to-list 'embark-around-action-hooks (list #'my-cua-enable-and-replace-in-rectangle #'embark--mark-target))
  (add-to-list 'embark-target-injection-hooks (list #'my-cua-enable-and-replace-in-rectangle #'embark--ignore-target))