Beamer presentation (metropolis theme) - \frametitle & \framesubtitle

Question

I am using beamer theme metropolis which does not support framesubtitles. I have therefore added it using \addtobeamertemplate. Unfortunately, I am not very familiar with latex.

Here are my issue:

• the framesubtitle is not left-aligned with the frametitle. How do I achieve this? (more generally: how do I change alignment for title and subtitle in general)
• the vertical spacing between frametitle and framesubtitle very small. How do I increase the spacing?

This is a minimum working example of my code:

\documentclass[8pt]{beamer}
\usetheme[block=fill]{metropolis}
\usepackage[utf8]{inputenc}


% Add framesubtitle to template
\setbeamercolor{framesubtitle}{fg=mDarkTeal}
\addtobeamertemplate{frametitle}{}{%
  \ifx\insertframesubtitle\@empty\else%
  \usebeamerfont{framesubtitle}%
  \usebeamercolor[fg]{framesubtitle}%
  %\vskip3pt
  \insertframesubtitle%
  \fi%
}



\begin{document}


\section{Chapter X}

\begin{frame}{Header 1}
    \framesubtitle{Subheader 2}

    Some text here!

\end{frame}

\end{document}

Thanks!

Answer 1

Only for example: main title to the right ans subtitle to the left:

\documentclass[8pt]{beamer}
\usetheme[block=fill]{metropolis}

\makeatletter
\setbeamercolor{framesubtitle}{fg=mDarkTeal}
\defbeamertemplate*{frametitle}{myframetitle}{%
    \nointerlineskip
    \begin{beamercolorbox}[%
        wd=\paperwidth,%
        sep=0pt,%
        leftskip=\metropolis@frametitle@padding,
        rightskip=\metropolis@frametitle@padding,
        ]{frametitle}%
        \metropolis@frametitlestrut@start
        \quad\insertframetitle%%%%%%%%%%%%%%%%%%%%%%
        \nolinebreak
        \metropolis@frametitlestrut@end
    \end{beamercolorbox}\par
    \usebeamerfont{framesubtitle}%
    \usebeamercolor[fg]{framesubtitle}%
    \vskip3pt
    \hspace*{-2.5\metropolis@frametitle@padding}%
    \insertframesubtitle
}
\makeatother
\setbeamertemplate{frametitle}[myframetitle]

\begin{document}

    \section{Chapter X}

    \begin{frame}{Header 1}
    \framesubtitle{Subheader 2}

    Some text here!

\end{frame}

\end{document}