I am using the Stix 2 fonts for some of my documents and am pretty happy with them except for one thing: I feel they place an excessive amount of vertical spacing around fraction lines in text style math. Here's a comparison to Latin Modern.

```latex
% !TeX program = lualatex
\documentclass{article}

\usepackage{fontspec}
\usepackage{unicode-math}

\newfontfamily\lmodern{LatinModernRoman}
\newfontfamily\stixii{StixTwoText}
\setmathfont{LatinModernMath}[version=lmodern]
\setmathfont{STIXTwoMath}[version=stix2]

\NewDocumentEnvironment{comparison}{ O{.48\textwidth} +b }{%
  \par
  \begin{minipage}{#1}%
    \lmodern
    \mathversion{lmodern}%
    \raggedleft
    #2%
  \end{minipage}\hfil
  \begin{minipage}{#1}%
    \stixii
    \mathversion{stix2}%
    \raggedright
    #2%
  \end{minipage}%
  \par\vskip 1ex\relax
}{}

\begin{document}\centering

\begin{comparison}
  Latin Modern vs Stix~2
\end{comparison}
\begin{comparison}
  \(\frac HH\)
\end{comparison}
\begin{comparison}
  \(\displaystyle
    \frac{ \frac HH }{ H + H }
  \)
\end{comparison}
\begin{comparison}
  \(\displaystyle
    H^{\frac HH}
  \)
\end{comparison}

\end{document}

```

[![MWE output](https://i.stack.imgur.com/9LvNN.png)](https://i.stack.imgur.com/9LvNN.png)

This leads to fractions being pretty much unusable in in-line math, which one might argue is a good thing (though I do not agree). But even in display math I find them taking up an unreasonable amount of space when appearing in nested fractions of in exponents. Note how the "middle" `H` in the nested fraction is closer to the big fraction line than to the small one. This just looks weird.

So my question is twofold:

* Is this really intended? What might be the reasons for making it so?
* Do I have any recourse for changing this without changing fonts? That is, is there some (La)TeX dimension I can adjust to reduce this space?