@SETLOCAL
@ECHO OFF
SET list=%~1
ECHO "LIST: %list%"
ECHO "ARG 1: %~1"
ECHO "ARG 2: %~2"
@ENDLOCAL
@GOTO :EOF

"LIST: blabla,blabla,>blabla"
"ARG 1: blabla,blabla,^>blabla"
"ARG 2: blaby"

@SETLOCAL
CALL :TEST "blabla,blabla,^>blabla", "blaby"
@ENDLOCAL
@GOTO :EOF

:TEST
@SETLOCAL
@ECHO OFF
SET list=%~1
ECHO "LIST: %list%"
ECHO "ARG 1: %~1"
ECHO "ARG 2: %~2"
@ENDLOCAL
@GOTO :EOF

"LIST: blabla,blabla,^"
"ARG 1: blabla,blabla,^^>blabla"
"ARG 2: blaby"

call test.bat "blabla,blabla,^>blabla", "blaby"

@echo off
setlocal
set arg1="blabla,blabla,^>blabla"
call :TEST %%arg1%% "blaby"
echo(
call call :TEST %%%%arg1%%%% "blaby"
::unquoted test
exit /b

:TEST
setlocal
set list=%~1
echo "LIST: %list%"
echo "ARG 1: %~1"
echo "ARG 2: %~2"
exit /b

"LIST: blabla,blabla,>blabla"
"ARG 1: blabla,blabla,^>blabla"
"ARG 2: blaby"

"LIST: blabla,blabla,>blabla"
"ARG 1: blabla,blabla,^>blabla"
"ARG 2: blaby"

C:test>test.bat "blabla,blabla,^>blabla" "blaby"
"LIST: blabla,blabla,>blabla"
"ARG 1: blabla,blabla,^>blabla"
"ARG 2: blaby"

C:test>set arg1="blabla,blabla,^>blabla"

C:test>test.bat %arg1% "blaby"
"LIST: blabla,blabla,>blabla"
"ARG 1: blabla,blabla,^>blabla"
"ARG 2: blaby"

C:test>call test.bat %^arg1% "blaby"
"LIST: blabla,blabla,>blabla"
"ARG 1: blabla,blabla,^>blabla"
"ARG 2: blaby"

C:test>set arg2=%^arg1%

C:test>call call test.bat %^arg2% "blaby"
"LIST: blabla,blabla,>blabla"
"ARG 1: blabla,blabla,^>blabla"
"ARG 2: blaby"

@echo off
setlocal enableDelayedExpansion
set "var1=!%~1!"
echo var1=!var1!

call :test var1
exit /b

:test
set "var2=!%~1!"
echo var2=!var2!

C:test>set complicatedString="This & that ^" ^& the other thing ^^ is 100% difficult to escape

C:test>set complicatedString
complicatedString="This & that ^" & the other thing ^ is 100% difficult to escape

C:test>test.bat complicatedString
var1="This & that ^" & the other thing ^ is 100% difficult to escape
var2="This & that ^" & the other thing ^ is 100% difficult to escape

C:test>call test.bat complicatedString
var1="This & that ^" & the other thing ^ is 100% difficult to escape
var2="This & that ^" & the other thing ^ is 100% difficult to escape

C:test>call call test.bat complicatedString
var1="This & that ^" & the other thing ^ is 100% difficult to escape
var2="This & that ^" & the other thing ^ is 100% difficult to escape

@SETLOCAL
CALL :TEST "blabla,blabla,^>blabla", "blaby"
@ENDLOCAL
@GOTO :EOF

:TEST
@SETLOCAL
@ECHO OFF
SET "list=%~1" & REM CHANGED
SET "list=%list:^^=^%" & REM ADDED
ECHO "LIST: %list%"
ECHO "ARG 1: %~1"
ECHO "ARG 2: %~2"
@ENDLOCAL
@GOTO :EOF

"LIST: blabla,blabla,^>blabla"
"ARG 1: blabla,blabla,^^>blabla"
"ARG 2: blaby"