Value or symbol handler with max argument error fix

I want to pass either a symbol or the value to lana-du-fpln.

(lana-du-fpln myplist)
(lana-du-fpln 'myplist)

I am getting Lisp error: (wrong-number-of-arguments #<subr max> 0)
  max()
  apply(max nil)
  (max 5 (apply #'max kl))

for this function

(defun lana-du-fpln (datenstruk)
  "Display HASH-TABLE contents in a dedicated buffer."

  (let* ( (bfr      (get-buffer-create (or bname "Lana DU")))

          (dtnm   (if (symbolp datenstruk) (symbol-name datenstruk) "Anonymous"))
          (dtvl   (if (symbolp datenstruk) (symbol-value datenstruk) datenstruk))
	  
          ;; Display width using key lengths
	  (kl  (map-apply
                 (lambda (key _value) (length (format "%s" key)))
                 dtvl))
          (wl  (max 5 (apply #'max kl)))
	  
	  (gwidth   2)
	  (fmt-str  (format "%%-%ds | %%-%ds | %%s\n" gwidth kwmax)) )

    (with-current-buffer bfr
      (read-only-mode 0)
      (erase-buffer)

      (map-do
        ;; FUNCITON
        (lambda (key value)
           (let* ( (fkey  (format "%s" key))
                   (fval  (format "%s" value))
                   (sgnl  (if (file-directory-p fval)
                                (propertize " " 'face lmps)
                            (propertize " " 'face lmpw)))
                   (pkey  (if (file-directory-p fval)
                                (propertize fkey 'face gjsf)
                            (propertize fkey 'face gjwf))) )
             (insert (format fmt-str sgnl pkey fval))))
        ;; MAP Data Structure (HASH-TABLE/PLIST/ALIST)
        dtvl)

      (goto-char (point-min)))

      (pop-to-buffer bfr)))