How to display beamer toc in appendix?

I am creating a beamer for a final exam project. Once I'm writing after \appendix, \tableofcontents won't appear. Any help here please?

TOC in introduction frame only shows sections and subsections, how can I also make appear subsubsections in TOC only in appendix frames?

Thank you a lot!

PS: I am using metropolistheme :)

% !TeX program = xelatex

\documentclass[10pt]{beamer}
\usetheme{metropolis}

\begin{document}
\section{A}
\section{B}
\begin{frame}
\tableofcontents
\end{frame}

\appendix
\begin{frame}
\tableofcontents
\end{frame}
\end{document}


• Normally beamer treats the appendix as a separate part. You can trick it by decreasing the part counter.

• To hide subsubsections from one of toc, you could use subsubsectionstyle=hide.

% !TeX program = xelatex

\documentclass[10pt]{beamer}
\usetheme{metropolis}

\begin{document}
\section{A}
\subsection{sub}
\subsubsection{subsub}
\begin{frame}
content...
\end{frame}
\section{B}
\subsection{sub}
\subsubsection{subsub}
\begin{frame}
\tableofcontents[subsubsectionstyle=hide]
\end{frame}

\appendix