Greek letter mu smaller than Latin characters in text and siunitx when using Noto font

Question

As per the title, when using the noto package to change the default font to Noto Sans I've noticed that the Greek letter mu inserted by siunitx doesn't match the font size of the regular text. The default font looks like this:

Where you can clearly see that the mu and m characters are the same height. When using Noto Sans (with detect-all as suggested in this question to set the siunitx font to match the standard text font), we can see that the mu character is now too small:

This problem isn't restricted to siunitx either, as when using the textgreek package to insert a regular mu into the text (the middle line in the example images) the character is also the wrong size.

Other Greek characters such as alpha and kappa match the latin text height in both Noto and the default font. Is there a way to correct the size of the mu character in Noto, or is this size difference by design?

Minimal working example used to generate the above images:

\documentclass[12pt]{report}
\usepackage{textgreek}
\usepackage{siunitx}

% Comment out to use original font
\usepackage[sfdefault]{noto}
\sisetup{detect-all}

\begin{document}
\noindent
Example siunitx: \SI{5}{\micro\metre}

\noindent
Example text:   5\textmu m

\noindent
Example maths: $5\mu m$

\end{document}

Answer 1

Use alphabeta rather than textgreek. The Noto Sans family supports Greek, so you don't want to make font family substitutions.

\documentclass[12pt]{report}
\usepackage{alphabeta}
\usepackage{siunitx}

% Comment out to use original font
\usepackage[sfdefault]{noto}

\sisetup{detect-all}

\begin{document}

Example siunitx: \SI{5}{\micro\metre}

Example text:   5\textmu m

Example maths: $5\mu m$

\end{document}

Answer 2

LaTeX thinks that noto doesn't have the symbol and so replaces it with the one from cmss which is much smaller.

You could e.g. change the class of noto from 7 to 6, but be aware that this could mean that LaTeX could try to use symbols from noto which the font doesn't provide. Classifying the textcomp support is not trivial, as every font is different here.

\documentclass[12pt]{report}
\usepackage{textgreek}
\usepackage{siunitx}
\tracinglostchars=3
% Comment out to use original font
\usepackage[sfdefault]{noto}
\DeclareEncodingSubset{TS1}{NotoSans-*}{6}
\sisetup{detect-all}
\begin{document}
\noindent
Example siunitx: \SI{5}{\micro\metre}

\noindent
Example text:   5\textmu m

\noindent
Example maths: $5\mu m$

\end{document}

Answer 3

Here is a solution with scale of the main fonts so that the possible fallback of the \textmu char will seem ok:

\documentclass[14pt]{extreport}

\usepackage{textgreek}
\usepackage{siunitx}

% Comment out to use original font
\usepackage[sfdefault,scale=0.85]{noto}
\sisetup{detect-all}

\begin{document}
\noindent
Example siunitx: \SI{5}{\micro\metre}

\noindent
Example text:   5\textmu m

\noindent
Example maths: $5\mu m$

\end{document}