\documentclass[aspectratio=169]{beamer}
\usetheme[progressbar=foot]{metropolis}           % Use metropolis theme

\usepackage{amsmath,graphicx}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{mathtools}
\usepackage{mathrsfs}
\usepackage{qrcode}
\usepackage{appendixnumberbeamer}

% Modifies beamer template, makes rwth corporate design colors available
\usepackage{netscipres}

\usepackage{tikz}
\usetikzlibrary{positioning}

\usepackage{duckuments}

\title{Netsci Presentation Template}
\date{\today}
\author{Your Name}
\institute{Computational Network Science}

% customize logos on title page (example: without text)
%\renewcommand{\titlelogo}{\includegraphics[height=5ex,keepaspectratio]{src/logo.pdf}}

% customize footer if you want
%\setbeamertemplate{frame footer}{\insertshortauthor{} ~\raisebox{1pt}{\tiny•}~ \insertshorttitle{}}

\begin{document}
  \maketitle

  \begin{frame}{Motivation}
    \vspace{-1.5mm}
    \Wider[5.2em]{\includegraphics[width=\linewidth,trim=0 57 0 60,clip]{src/bg.jpg}
    
    {\vspace{-18pt}\textcolor{white}{~\resizebox{1.5cm}{!}{Image by Josef Hoppe (CC-BY-SA)}}}\hfill}

  \end{frame}

  \begin{frame}{Adding Wider figures}
    \centering

    A normal line\\
    \hrulefill

    \vspace{1.5em}

    \Wider{ %automatically centers
      A wider line\\
      \hrulefill
    }

    \vspace{1.5em}
    
    \Wider{ %automatically centers
      \raggedright
      A wider, left-aligned text\\
      \hrulefill
    }

    \vspace{1.5em}

    \Wider[5em]{
      A very wide line\\
      \hrulefill
    }
  \end{frame}

  \begin{frame}{Conclusion}
    \begin{minipage}{.7\linewidth}
      \begin{itemize}
        \item Great
        \item Things
        \begin{itemize}
          \item (also subthings)
        \end{itemize}
        \item You did in your work!
        \item A lot of space, and it will linebreak with sufficient space to the QR code on the right.
      \end{itemize} 
    \end{minipage}
    \hfil
    \begin{minipage}{.2\linewidth}
      \centering
      \textcolor{rwthblue}{\qrcode[height=\linewidth,level=L]{https://hoppe.io}}
      \vspace{0cm} % renders weird without this

      QR code for the audience
    \end{minipage}
  \end{frame}

  \appendix % ensure that only content slides are counted for the progress slider.

  \begin{frame}{Additional Plots}
    \Wider{
    \begin{minipage}[b]{.49\linewidth}\centering
      \includegraphics[width=\linewidth]{example-image-duck}
      
      (not) very important experiment!
    \end{minipage}
    \hfill
      \begin{minipage}[b]{.49\linewidth}\centering
        \includegraphics[width=\linewidth]{example-image-duck}
        
        Comparison to the previous state of the art
    \end{minipage}
    }
  \end{frame}

\end{document}