once apply_ps lisp function runs successfully and applies the given page setup to all layouts, then the NONE should no longer show up when you enter the PLOT command. The default on all the layouts should be the given page setup name you entered. The issue you're encountering within the PLOT command does not occur for me so I cannot replicate the problem.
As for actually setting all layouts to a default page setup to none, I've modified the lisp function to accommodate. Now when you enter the page setup name "*none*" or "*NONE*" apply_ps will set all layouts back to default page setup of NONE:
; apply_ps function applies given pagesetup name to all layouts
; response to OP:
; https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/assign-a-page-setup-to-all-layout-tabs-prior-to-or-without-going/m-p/11754621/highlight/false#M443744
(defun c:apply_ps (/ allPageSetupsOfLayoutType psname putPagesetup putPageSetupNone)
; https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/lisp-for-page-setup/td-p/9386936
; arguments:
; document - (vla-get-activedocument(vlax-get-acad-object))
; layout - (getvar"ctab")
; setup - existing pagesetup name
; Usage:
; (putPagesetup (vla-get-activedocument(vlax-get-acad-object)) (getvar"ctab") "PageSetup Paper") ; given existing pagesetup name: "PageSetup Paper"
; Jason Piercey
(defun putPagesetup (document layout setup)
(if
(vl-catch-all-error-p (vl-catch-all-apply
(function
(lambda ()
(vla-copyfrom (vla-item (vla-get-layouts document) layout) (vla-item (vla-get-plotconfigurations document) setup))
)
)
)
)
nil t
)
) ; defun
; putPageSetupNone function sets page setup to empty string
(defun putPageSetupNone (layout / dn laydict psn)
(setq dn (cdr (assoc -1 (dictsearch (namedobjdict) "ACAD_LAYOUT"))))
(setq laydict (dictsearch dn layout))
(entmod(subst(cons 1 "")(assoc 1 laydict)laydict))
) ; defun
;;; https://jtbworld.com/autocad-pagesetup-lsp
;;;--- allPageSetupsOfLayoutType function given autocad drawing returns Layout Pagesetups sorted
;;; (allPageSetupsOfLayoutType <AcadDocument>)
;;; (allPageSetupsOfLayoutType (vla-get-activedocument (vlax-get-acad-object)))
;;; credits to Jimmy Bergmark
(defun allPageSetupsOfLayoutType (doc / aps)
(vlax-for pc (vla-get-plotconfigurations doc)
(if (= (vla-get-ModelType pc) :vlax-false)
(setq aps (cons (vla-get-name pc) aps))
)
)
(vl-sort aps '<)
) ; defun
(if (> (strlen (setq psname (getstring "\nEnter Page Setup Name: " T))) 0)
(if (or
(member psname (allPageSetupsOfLayoutType (vla-get-activedocument (vlax-get-acad-object))))
(eq (strcase psname) "*NONE*")
)
(progn
(foreach itm (layoutlist)
(if (eq (strcase psname) "*NONE*")
(putPageSetupNone itm)
(putPagesetup (vla-get-activedocument(vlax-get-acad-object)) itm psname)
) ; if
) ; foreach
(princ(strcat"\nPage Setup Name: [" psname "] Successfully Applied to All Layouts."))(princ)
)
(progn
(princ(strcat"\nPage Setup Name: [" psname "] Not Found."))(princ)
)
)
(progn
(princ"\nNo Page Setup Name Entered.")(princ)
)
) ; if
) ; defun apply_ps