\RequirePackage{pdfmanagement-testphase}
\DeclareDocumentMetadata{uncompress,pdfversion=2.0}
\documentclass{article}
\usepackage{unicode-math,tagpdf,amsmath,luamml}
\tagpdfsetup{activate-all,interwordspace=true,}
\ExplSyntaxOn
\let\BLUB\luamml_flag_structelem:
\ExplSyntaxOff
\begin{document}\tracingmathml=2
\tagstructbegin{tag=Document}
\tagstructbegin{tag=Formula}
\[
x_{1/2}=-\frac p2\pm\sqrt{\frac{p^2}4-q}
\BLUB
\]
\tagstructend
\tagstructend
\end{document}