mathtools, amsart, appendix, autoref fails (fix of issue 311 does not work)

Hi
A year ago a fix (isseu 311) solved the problem concerning the interaction between autoref and mathtools,
However the fix fails for amsart together with appendix style as the following MWE shows

\documentclass[12pt,reqno]{amsart}
\usepackage{appendix}
\usepackage{amsmath,amsthm}
\usepackage{mathtools}
\mathtoolsset{showonlyrefs}
\usepackage[colorlinks]{hyperref}

\makeatletter
\AddToHook{package/mathtools/after}{%
  \def\HyRef@autoref#1#2{%
    \begingroup
      \Hy@safe@activestrue
      \@nameuse{MH_if_boolean:nT}{show_only_refs}{%
        % excerpted from \noeqref in mathtools.sty
        \edef\@tempa{#2}%
        %% will be done in \HyRef@autosetref
        % \@ifundefined{r@\@tempa}{%
        %   \protect\G@refundefinedtrue%
        %   \@latex@warning{Reference `\@tempa' on page \thepage \space
        %     undefined (\string\noeqref)}%
        % }{}%
        \if@filesw
          \protected@write\@auxout{}{\string\MT@newlabel{\@tempa}}%
        \fi
      }%
      \expandafter\HyRef@autosetref\csname r@#2\endcsname{#2}{#1}%
    \endgroup
  }
}
\makeatother
\newcommand\autoeqref[1]{\noeqref{#1}\autoref{#1}}
\begin{document}
\section{title}\label{sec:a}
\begin{appendices}
\begin{gather}
  \int f   dx = 0\label{eq:1} \\
  \int f_2 dx = 0\label{eq:2} \\
  \int f_3 dx = 0 \label{eq:3}
\end{gather}
% the most recent label before using \label{eq:1} is referenced
See \autoref{eq:1}  does work
% this makes equation labeled "eq:2" numbered
See \eqref{eq:2} woks
\end{appendices}
\end{document}

Any idea how fix this problem?
Thanks
Uwe Brauer

Start with the provided minimal working example and compare it with issue 311. Inspect the interaction between mathtools.sty, the package/mathtools/after hook, \HyRef@autoref, and \HyRef@autosetref, including the \noeqref excerpt. Done means the example works with amsart, appendix, mathtools showonlyrefs, and autoref for the cited equations.