titlepage-geometry Problem

\documentclass[%
   paper=a4,
   fontsize=12pt,
   BCOR=2mm,
   parskip=half*,
]{scrartcl}
\usepackage{filecontents}
 
\begin{filecontents}{dhbwstyle.sty}
\NeedsTeXFormat{LaTeX2e}[1995/06/01]
\ProvidesPackage{dhbwstyle}[2019/07/02 v0.1]
\RequirePackage{scrbase}
\RequirePackage{calc}
\RequirePackage{setspace}
\RequirePackage{tocbasic}
\RequirePackage[%
section,
nomain,
nopostdot,
nonumberlist,
abbreviations
]{glossaries-extra}
\RequirePackage[autostyle]{csquotes}
\RequirePackage{geometry}
\RequirePackage{scrlayer-scrpage}
\setstretch{1.433}
\geometry{left=30mm, right=25mm, top=25mm, bottom=15mm, bindingoffset=2mm}
\setlength{\footheight}{21pt}
\setlength{\headheight}{21pt}
\providecommand*{\reftitle}{\@title}
\providecommand*{\refauthor}{\@author}
\providecommand*{\refdate}{\@date}
\providecommand*{\refplace}{\@place}
\providecommand*{\labeldate}{vorgelegt am}
\providecommand*{\labelfaculty}{Fakultät}
\providecommand*{\labeldiscipline}{Studiengang}
\providecommand*{\labelcourse}{Studienjahrgang/Kurs}
\providecommand*{\labelsemester}{Studienhalbjahr}
\providecommand*{\labelfrom}{von}
\providecommand*{\labelcompany}{Ausbildungspartner}
\providecommand*{\labeladvisor}{Wissenschaftlicher Betreuer}
\end{filecontents}
 
\begin{filecontents}{title-DHBWW.def}
\ProvidesFile{titleDHBWW.def}[2019/06/27 v0.1]
\DefineFamilyMember[DHBWW]{title}
\setkomafont{title}{\fontsize{14pt}{18pt}\selectfont\bfseries}
\setkomafont{subject}{\fontsize{12pt}{14pt}\selectfont\bfseries}
\newlength{\titlepagewidth}
\setlength{\titlepagewidth}{\textwidth}
\renewcommand*{\makemaintitle}{%
   \begin{fullsizetitle}
      \setlength{\parskip}{\z@}
      \setlength{\parindent}{\z@}
      \setlength{\parfillskip}{\z@\@plus 1fil}
      \linespread{1.5}\selectfont
      \@titlepagefont
      \centering
      \vspace*{25mm}
      \begin{minipage}[t]{\titlepagewidth}
         \begin{minipage}{\titlepagewidth}
            \centering
            {\titlefont{\@title}}\par%
            \vspace*{7ex}%
            {\subject@font{\@subject}}\par%
         \end{minipage}\par%
         \vspace*{10ex}%
         \begin{tabular}{@{}p{.4\titlepagewidth}p{.5\titlepagewidth}@{}}
            \labeldate:       & \@date\\
            \labelfaculty:    & \@faculty\\
            \labeldiscipline: & \@discipline\\
            \labelcourse:     & \@course\\
            \labelsemester:   & \@duration
         \end{tabular}\par%
         \vspace*{10ex}%
         \begin{minipage}{\titlepagewidth}
            \centering
            \labelfrom\par%
            \@author\par
         \end{minipage}\par%
         \vspace*{15ex}
         \begin{minipage}{0.55\titlepagewidth}
            \labelcompany\newline
            \@company
         \end{minipage}\hfill
         \begin{minipage}{0.35\titlepagewidth}
            \labeladvisor\newline
            \@advisor
         \end{minipage}\par%
      \end{minipage}%
   \end{fullsizetitle}%
}%
\endinput
\end{filecontents}
 
\usepackage{polyglossia}
\usepackage{fontspec}
\setmainlanguage[variant=german, spelling=new, babelshorthands=true]{german}
\usepackage{scrlayer-scrpage}
\usepackage{dhbwstyle}
\usepackage[DHBWW]{titlepage}
 
\begin{document}
   \title{Der Wandel eines deutschen PVH-Großhändlers -- Eine Analyse }
   \subject{PROJEKTARBEIT II}
   \date{\today}
   \author{Max Mustermann}
   \faculty{Wirtschaft}
   \discipline{BWL-Handel}
   \course{CC~01}
   \duration{SS2009}
   \place{Stuttgart}
   \advisor{Prof. Dr. Bilbo Baggins\\ Studiengangsleiter\\ BWL-Handel}
   \company{Gebr. Laster KG\\ Einsamer Berg 15\\ 71006~Mordor}
   \maketitle
\end{document}