\documentclass[12pt]{report}

\usepackage[a-2u]{pdfx}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{lmodern}

\input{metadata}
\input{todos}

\begin{document}
\ifEN
Czech abstract is not available
\else\Abstract\fi
\end{document}