Changing font properties within the tikz environment only [closed]

Question

I often annotate figures within the tikz environment. For example

\documentclass[12pt]{report}

\usepackage[T1]{fontenc}
\usepackage{Baskervaldx}
\usepackage[Baskervaldx,upint]{newtxmath}

\usepackage{tikz}
    \usetikzlibrary{arrows,arrows.meta,patterns,decorations,shapes.geometric}
    \usetikzlibrary{decorations.markings,decorations.pathmorphing,decorations.pathreplacing}    

\begin{document}

    \begin{figure}[h] 
       \centering        
       \begin{tikzpicture}
          \node[anchor=south west,inner sep=0] at (0,0) 
          {
            \includegraphics[width=1.0\textwidth]{Images/MyImage.pdf}
          };
          \begin{scope}
             \draw[decoration={brace,raise=0mm},decorate] (58.4mm,37mm)--(80.1mm,37mm)node[above,align=center,midway,sloped]{here is some text};
          \end{scope}
        \end{tikzpicture}
        \caption{Oh Caption, my Caption...}
        \label{MyFigure}
     \end{figure}

\end{document}

I'd like to reduce the font size whenever I call the tikzpicture environment, as at the moment it seems to just be set at by the document global font settings.

So I would like to keep the rest of the document font settings (font families, font size, etc.) as I have defined them, but make the font inside tikzpicture environment