How to close a bat after a specific time without intrerupting the execution?

To make it start maximized put this at the top of your script, below @echo off

if not "%1" == "max" start /MAX cmd /c %0 max & exit/b

I'll update this answer later with the other part, but I think opening a new batch with a timeout as soon as this one starts with start /B should help a lot.

EDIT

So this starts your script with a second script in it. That second script kills the first script and starts a third cmd to delete itself:

@echo off
if not "%1" == "max" start /MAX cmd /c %0 max & exit/b
set T=%TEMP%\sthUnique.tmp
wmic process where (Name="WMIC.exe" AND CommandLine LIKE "%%%TIME%%%") get ParentProcessId /value | find "ParentProcessId" >%T%
set /P A=<%T%
SET PID=%A:~16%
echo @echo off > killParent.bat
:: replace the 5 on the next line with any other number
echo timeout /t 5 /nobreak >> killParent.bat
echo start "" cmd ^/c timeout ^/t 1^^^&del "%%~f0"^^^&exit ^/b >> killParent.bat
echo taskkill /f /PID %PID% >> killParent.bat
START /B CMD /C CALL killParent.bat >NUL 2>&1
::any logic here instead of pause
pause

Place your code where the pause is and replace the 5 with the number of seconds you want to wait.

This does have the drawback of not being able to finish before the timer runs out, you can fix that by putting echo title parentKiller >> killParent.bat below echo @echo off > killParent.bat and putting

del killParent.bat
taskkill /F /FI "WINDOWTITLE eq parentKiller *" /T

at the end of your execution path, so at the bottom of your batch file normally. This would then look like this:

@echo off
if not "%1" == "max" start /MAX cmd /c %0 max & exit/b
set T=%TEMP%\sthUnique.tmp
wmic process where (Name="WMIC.exe" AND CommandLine LIKE "%%%TIME%%%") get ParentProcessId /value | find "ParentProcessId" >%T%
set /P A=<%T%
SET PID=%A:~16%
echo @echo off > killParent.bat
echo title parentKiller >> killParent.bat
:: replace the 5 on the next line with any other number
echo timeout /t 5 /nobreak >> killParent.bat
echo start "" cmd ^/c timeout ^/t 1^^^&del "%%~f0"^^^&exit ^/b >> killParent.bat
echo taskkill /f /PID %PID% >> killParent.bat
START /B CMD /C CALL killParent.bat >NUL 2>&1
::any logic here instead of pause
pause
del killParent.bat
taskkill /F /FI "WINDOWTITLE eq parentKiller *" /T