\DocumentMetadata{tagging = on}
\documentclass{ltx-talk}

\usepackage{fancyvrb}

\begin{document}

\begin{frame*}
  Text
  \begin{actionenv}<+-|alert@+>
    \begin{Verbatim}[gobble = 6]
      Some content
      %#$_\
      XXX
    \end{Verbatim}
  \end{actionenv}
  \uncover<+->{More text}
\end{frame*}

\end{document}