rotate display using applescript, tested on Mac os High Sierra(10.13)

route-screen.applescript

--
--	Created by: v1c77
--	Created on: 2018/7/21
--
--             DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
--                       Version 2, December 2004

--      Copyright (C) 2020 v1c77

--      Everyone is permitted to copy and distribute verbatim or modified
--      copies of this license document, and changing it is allowed as long
--      as the name is changed.

--               DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
--      TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

--      0. You just DO WHAT THE FUCK YOU WANT TO.

use AppleScript version "2.7" -- Yosemite (10.10) or later
use scripting additions


tell application "System Preferences"
	quit
	delay 0.5
	launch
	activate
	set current pane to pane "com.apple.preference.displays"
	--reveal pane id "com.apple.preference.displays"
end tell

tell application "System Events"
	tell application process "System Preferences"
		tell window "DELL U2415" -- change the window name for different display
			delay 1
			click radio button "Display" of tab group 1
			set theGroup to tab group 1
			tell pop up button "Rotation:" of theGroup
				set theStat to value of it
				click
				tell menu 1
					if theStat = "Standard" then
						click menu item 4 -- 270 dig
					else
						click menu item 1 -- standard
					end if
				end tell
			end tell
		end tell
	end tell
end tell
tell application "System Preferences"
	quit
end tell

I ended up using displayplacer only, avoiding opening Settings at all.

I have an Automator workflow with Run AppleScript action:

on run {input, parameters}
	-- Run displayplacer list to get the current display configurations
	set displayplacerOutput to do shell script "/opt/homebrew/bin/displayplacer list"
	
	-- ID of the monitor you'll rotate
	set targetDisplayID to "8B54EED0-06DA-6D6D-0857-D6964E3302DB"
	
	-- Extract the last line of the output
	set lastLine to paragraph -1 of displayplacerOutput
	
	
	-- Safely extract the degree parameter for the target display from the last line
	-- First, identify the correct section of the last line
	set grepCommand to "echo " & (quoted form of lastLine) & " | grep -o 'id:" & targetDisplayID & ".*degree:[0-9]*'"
	
	set targetDisplaySection to do shell script grepCommand
	
	-- Extract the degree value
	set degreeParameter to do shell script "echo " & (quoted form of targetDisplaySection) & " | grep -o 'degree:[0-9]*'"
	
	set currentDegree to word 2 of degreeParameter
	
	-- Determine the new rotation based on the current rotation
	if currentDegree = "0" then
		-- vertical arrangement
		do shell script "/opt/homebrew/bin/displayplacer \"id:8B54EED0-06DA-6D6D-0857-D6964E3302DB res:1692x3008 scaling:on origin:(0,-3008) degree:90\""
	else
		-- horizontal arrangement
		do shell script "/opt/homebrew/bin/displayplacer \"id:8B54EED0-06DA-6D6D-0857-D6964E3302DB res:2560x1440 scaling:on origin:(-427,-1440) degree:0\""
	end if
end run

to use this script you'll need

• figure out where your displayplacer is by running where displayplacer (mine is in /opt/homebrew/bin/displayplacer)
• get your target display ID (the one you're rotating) by running displayplacer list and checking output in the end
• get configs for vertical and horizontal arrangement. To do this, arrange manually your perfect vertical/horizontal setup, run displayplacer list and see the output in the end.
  Note, the arrangement configs could be anything, e.g. in my case my vertical setup has higher resolution than horizontal.

This script runs MUCH faster since it does not need to run Settings and any UI.