[Tex/LaTex] Metropolis beamer title page

Question

Using Metropolis theme, I set this title page:

\documentclass[12pt]{beamer}

\usetheme[progressbar=frametitle]{metropolis}
\usepackage{appendixnumberbeamer}

\setbeamertemplate{title page}{
    \begin{minipage}[c][\paperheight]{\textwidth}
        \ifx\inserttitlegraphic\@empty\else\usebeamertemplate*{title graphic}\fi
        \vfill%
        \ifx\inserttitle\@empty\else\usebeamertemplate*{title}\fi
        \ifx\insertsubtitle\@empty\else\usebeamertemplate*{subtitle}\fi
        \usebeamertemplate*{title separator}
        \begin{minipage}[t]{.5\textwidth}
            \ifx\beamer@shortauthor\@empty\else\usebeamertemplate*{author}\fi
            \ifx\insertdate\@empty\else\usebeamertemplate*{date}\fi
            \ifx\insertinstitute\@empty\else\usebeamertemplate*{institute}\fi
        \end{minipage}
        \begin{minipage}[t]{.5\textwidth}
            \vspace*{2em}
            {\hspace{3.2em}\small Supervisor: \textit{name} \par}
            \vspace*{0.2em}
            {\hspace{3.2em}\small CoSupervisor: \textit{name}}
        \end{minipage}%
        \vfill
        \vspace*{1mm}
    \end{minipage}
}
\definecolor{Cream}{RGB}{255,253,208}
\definecolor{AirForce}{RGB}{88,139,174}
%\setbeamercolor{frametitle}{bg=Cream, fg=AirForce}

\usepackage{multicol}
\usepackage{tabularx}
\usepackage{multirow}
\usepackage{makecell}
\usepackage[utf8]{inputenc} 
\usepackage[T1]{fontenc} 
\usepackage[export]{adjustbox}
\usepackage{enumitem}
\usepackage{pifont}
\usepackage{wasysym}
\usepackage{amsfonts}
\setlist[itemize]{label=$\checkmark$}
%\newcommand{\Icon}{\includegraphics[width=1em]{fig/icon.jpg}}

\definecolor{honey}{RGB}{255,195,11}

\usepackage{booktabs}
\usepackage[scale=2]{ccicons}

\usepackage{pgfplots}
\usepgfplotslibrary{dateplot}

\usepackage{xspace}
\newcommand{\themename}{\textbf{\textsc{metropolis}}\xspace}

\title{title}
\subtitle{subtitle}
% \date{\today}
\date{date}
\author{Author}
\institute{Master Degree in \\networks}
% \titlegraphic{\hfill\includegraphics[height=1.5cm]{logo.pdf}}

\begin{document}

\maketitle



\end{document}

I would like to:
-put the \institute part in the center-bottom of the page;
-put title and subtitle at the center of the page.

I tried some combination with \centering but they didn't work

Answer 1

Based on https://tex.stackexchange.com/a/388878/36296 you could redefine your title page like this:

\documentclass[12pt]{beamer}

\usetheme[progressbar=frametitle]{metropolis}
\usepackage{appendixnumberbeamer}

\setbeamertemplate{title page}{
    \begin{minipage}[c][\paperheight]{\textwidth}
        \ifx\inserttitlegraphic\@empty\else\usebeamertemplate*{title graphic}\fi
        \vfill%
        {
        \centering
        \ifx\inserttitle\@empty\else\usebeamertemplate*{title}\fi
        \ifx\insertsubtitle\@empty\else\usebeamertemplate*{subtitle}\fi
        }
        \usebeamertemplate*{title separator}
        \begin{minipage}[t]{.5\textwidth}
            \ifx\beamer@shortauthor\@empty\else\usebeamertemplate*{author}\fi
            \ifx\insertdate\@empty\else\usebeamertemplate*{date}\fi
        \end{minipage}
        \begin{minipage}[t]{.5\textwidth}
            \vspace*{2em}
            {\hspace{3.2em}\small Supervisor: \textit{name} \par}
            \vspace*{0.2em}
            {\hspace{3.2em}\small CoSupervisor: \textit{name}}
        \end{minipage}%

        \begin{minipage}[t]{\textwidth}
            \centering
            \ifx\insertinstitute\@empty\else\usebeamertemplate*{institute}\fi
        \end{minipage}
        \vfill
        \vspace*{1mm}
    \end{minipage}
}


\setbeamertemplate{title}{
%  \raggedright%  % <-- Comment here
  \linespread{1.0}%
  \inserttitle%
  \par%
  \vspace*{0.5em}
}
\setbeamertemplate{subtitle}{
%  \raggedright%  % <-- Comment here
  \insertsubtitle%
  \par%
  \vspace*{0.5em}
}

\definecolor{Cream}{RGB}{255,253,208}
\definecolor{AirForce}{RGB}{88,139,174}
%\setbeamercolor{frametitle}{bg=Cream, fg=AirForce}

\usepackage{multicol}
\usepackage{tabularx}
\usepackage{multirow}
\usepackage{makecell}
\usepackage[utf8]{inputenc} 
\usepackage[T1]{fontenc} 
\usepackage[export]{adjustbox}
\usepackage{enumitem}
\usepackage{pifont}
\usepackage{wasysym}
\usepackage{amsfonts}
\setlist[itemize]{label=$\checkmark$}
%\newcommand{\Icon}{\includegraphics[width=1em]{fig/icon.jpg}}

\definecolor{honey}{RGB}{255,195,11}

\usepackage{booktabs}
\usepackage[scale=2]{ccicons}

\usepackage{pgfplots}
\usepgfplotslibrary{dateplot}

\usepackage{xspace}
\newcommand{\themename}{\textbf{\textsc{metropolis}}\xspace}

\title{title}
\subtitle{subtitle}
% \date{\today}
\date{date}
\author{Author}
\institute{Master Degree in \\networks}
% \titlegraphic{\hfill\includegraphics[height=1.5cm]{logo.pdf}}

\begin{document}

\maketitle



\end{document}