Ok you need to look at Aeccoreconsole it will run without opening drawings.
The attached code is for plotting a range of layouts in a dwg so would suit your needs, it would need to be changed slightly to accept the layout range from a script etc. Edit the following.
(defun AH:pltlays (numlay numend / lay)
(SETVAR "PDMODE" 0)
(setvar "fillmode" 1)
(setvar "textfill" 1)
(setq alllays (vla-get-Layouts (vla-get-activedocument (vlax-get-acad-object))))
(setq count (vla-get-count alllays))
;(if (not AH:getvalsm)(load "Multi Getvals.lsp"))
;(setq vals (AH:getvalsm (list "Enter plot range" "Enter start tab number" 6 4 "1" "Enter end tab number" 6 4 (RTOS COUNT 2 0))))
;(setq numlay (atoi (nth 0 vals)))
;(setq numend (atoi (nth 1 vals)))
Ok so a typical Aeccoreconsole is ran from a batch file
:: Path to AutoCAD core console
set accoreexe="C:\Program Files\Autodesk\AutoCAD 2020\accoreconsole.exe"
:: Path to the script to run
set script="C:\Users\[USERNAME]\Desktop\TESTER\tester2.scr"
%accoreexe% /i C:\Users\[USERNAME]\Desktop\IPAD\TESTER\TEST1.dwg /s %script%
%accoreexe% /i C:\Users\[USERNAME]\Desktop\IPAD\TESTER\TEST2.dwg /s %script%
%accoreexe% /i C:\Users\[USERNAME]\Desktop\IPAD\TESTER\TEST3.dwg /s %script%
%accoreexe% /i C:\Users\[USERNAME]\Desktop\IPAD\TESTER\TEST4.dwg /s %script%
%accoreexe% /i C:\Users\[USERNAME]\Desktop\IPAD\TESTER\TEST5.dwg /s %script%
The script file would be
(load "plotpdfrange")
(AH:pltlays 1 100)
plotA3Pdfrange.lsp