\wide[bar/hat/tilde] commands with unicode-math

Question

Is there some way to get \widebar, \widehat, and \widetilde to work with the libertinus package, such as to get nice spacing?

Here's a MWE (which uses Vogt's \widebar command):

\documentclass{article}
\usepackage{libertinus}
\makeatletter
\let\save@mathaccent\mathaccent
\newcommand*\if@single[3]{%
  \setbox0\hbox{${\mathaccent"0362{#1}}^H$}%
  \setbox2\hbox{${\mathaccent"0362{\kern0pt#1}}^H$}%
  \ifdim\ht0=\ht2 #3\else #2\fi
  }
%The bar will be moved to the right by a half of \macc@kerna, which is computed by amsmath:
\newcommand*\rel@kern[1]{\kern#1\dimexpr\macc@kerna}
%If there's a superscript following the bar, then no negative kern may follow the bar;
%an additional {} makes sure that the superscript is high enough in this case:
\newcommand*\widebar[1]{\@ifnextchar^{{\wide@bar{#1}{0}}}{\wide@bar{#1}{1}}}
%Use a separate algorithm for single symbols:
\newcommand*\wide@bar[2]{\if@single{#1}{\wide@bar@{#1}{#2}{1}}{\wide@bar@{#1}{#2}{2}}}
\newcommand*\wide@bar@[3]{%
  \begingroup
  \def\mathaccent##1##2{%
%Enable nesting of accents:
    \let\mathaccent\save@mathaccent
%If there's more than a single symbol, use the first character instead (see below):
    \if#32 \let\macc@nucleus\first@char \fi
%Determine the italic correction:
    \setbox\z@\hbox{$\macc@style{\macc@nucleus}_{}$}%
    \setbox\tw@\hbox{$\macc@style{\macc@nucleus}{}_{}$}%
    \dimen@\wd\tw@
    \advance\dimen@-\wd\z@
%Now \dimen@ is the italic correction of the symbol.
    \divide\dimen@ 3
    \@tempdima\wd\tw@
    \advance\@tempdima-\scriptspace
%Now \@tempdima is the width of the symbol.
    \divide\@tempdima 10
    \advance\dimen@-\@tempdima
%Now \dimen@ = (italic correction / 3) - (Breite / 10)
    \ifdim\dimen@>\z@ \dimen@0pt\fi
%The bar will be shortened in the case \dimen@<0 !
    \rel@kern{0.6}\kern-\dimen@
    \if#31
      \overline{\rel@kern{-0.6}\kern\dimen@\macc@nucleus\rel@kern{0.4}\kern\dimen@}%
      \advance\dimen@0.4\dimexpr\macc@kerna
%Place the combined final kern (-\dimen@) if it is >0 or if a superscript follows:
      \let\final@kern#2%
      \ifdim\dimen@<\z@ \let\final@kern1\fi
      \if\final@kern1 \kern-\dimen@\fi
    \else
      \overline{\rel@kern{-0.6}\kern\dimen@#1}%
    \fi
  }%
  \macc@depth\@ne
  \let\math@bgroup\@empty \let\math@egroup\macc@set@skewchar
  \mathsurround\z@ \frozen@everymath{\mathgroup\macc@group\relax}%
  \macc@set@skewchar\relax
  \let\mathaccentV\macc@nested@a
%The following initialises \macc@kerna and calls \mathaccent:
  \if#31
    \macc@nested@a\relax111{#1}%
  \else
%If the argument consists of more than one symbol, and if the first token is
%a letter, use that letter for the computations:
    \def\gobble@till@marker##1\endmarker{}%
    \futurelet\first@char\gobble@till@marker#1\endmarker
    \ifcat\noexpand\first@char A\else
      \def\first@char{}%
    \fi
    \macc@nested@a\relax111{\first@char}%
  \fi
  \endgroup
}
\makeatother
\begin{document}
\[\widebar{a}\hspace{1pt}\widebar{b}\hspace{1pt}\widebar{c}\hspace{1pt}\widebar{d}\hspace{1pt}\widebar{e}\hspace{1pt}\widebar{f}\hspace{1pt}\widebar{g}\hspace{1pt}\widebar{h}\hspace{1pt}\widebar{i}\hspace{1pt}\widebar{j}\hspace{1pt}\widebar{k}\hspace{1pt}\widebar{l}\hspace{1pt}\widebar{m}\hspace{1pt}\widebar{n}\hspace{1pt}\widebar{o}\hspace{1pt}\widebar{p}\hspace{1pt}\widebar{q}\hspace{1pt}\widebar{r}\hspace{1pt}\widebar{s}\hspace{1pt}\widebar{t}\hspace{1pt}\widebar{u}\hspace{1pt}\widebar{v}\hspace{1pt}\widebar{w}\hspace{1pt}\widebar{x}\hspace{1pt}\widebar{y}\hspace{1pt}\widebar{z}\]
\[\widebar{A}\hspace{1pt}\widebar{B}\hspace{1pt}\widebar{C}\hspace{1pt}\widebar{D}\hspace{1pt}\widebar{E}\hspace{1pt}\widebar{F}\hspace{1pt}\widebar{G}\hspace{1pt}\widebar{H}\hspace{1pt}\widebar{I}\hspace{1pt}\widebar{J}\hspace{1pt}\widebar{K}\hspace{1pt}\widebar{L}\hspace{1pt}\widebar{M}\hspace{1pt}\widebar{N}\hspace{1pt}\widebar{O}\hspace{1pt}\widebar{P}\hspace{1pt}\widebar{Q}\hspace{1pt}\widebar{R}\hspace{1pt}\widebar{S}\hspace{1pt}\widebar{T}\hspace{1pt}\widebar{U}\hspace{1pt}\widebar{V}\hspace{1pt}\widebar{W}\hspace{1pt}\widebar{X}\hspace{1pt}\widebar{Y}\hspace{1pt}\widebar{Z}\]
\[\widetilde{a}\hspace{1pt}\widetilde{b}\hspace{1pt}\widetilde{c}\hspace{1pt}\widetilde{d}\hspace{1pt}\widetilde{e}\hspace{1pt}\widetilde{f}\hspace{1pt}\widetilde{g}\hspace{1pt}\widetilde{h}\hspace{1pt}\widetilde{i}\hspace{1pt}\widetilde{j}\hspace{1pt}\widetilde{k}\hspace{1pt}\widetilde{l}\hspace{1pt}\widetilde{m}\hspace{1pt}\widetilde{n}\hspace{1pt}\widetilde{o}\hspace{1pt}\widetilde{p}\hspace{1pt}\widetilde{q}\hspace{1pt}\widetilde{r}\hspace{1pt}\widetilde{s}\hspace{1pt}\widetilde{t}\hspace{1pt}\widetilde{u}\hspace{1pt}\widetilde{v}\hspace{1pt}\widetilde{w}\hspace{1pt}\widetilde{x}\hspace{1pt}\widetilde{y}\hspace{1pt}\widetilde{z}\]
\[\widetilde{A}\hspace{1pt}\widetilde{B}\hspace{1pt}\widetilde{C}\hspace{1pt}\widetilde{D}\hspace{1pt}\widetilde{E}\hspace{1pt}\widetilde{F}\hspace{1pt}\widetilde{G}\hspace{1pt}\widetilde{H}\hspace{1pt}\widetilde{I}\hspace{1pt}\widetilde{J}\hspace{1pt}\widetilde{K}\hspace{1pt}\widetilde{L}\hspace{1pt}\widetilde{M}\hspace{1pt}\widetilde{N}\hspace{1pt}\widetilde{O}\hspace{1pt}\widetilde{P}\hspace{1pt}\widetilde{Q}\hspace{1pt}\widetilde{R}\hspace{1pt}\widetilde{S}\hspace{1pt}\widetilde{T}\hspace{1pt}\widetilde{U}\hspace{1pt}\widetilde{V}\hspace{1pt}\widetilde{W}\hspace{1pt}\widetilde{X}\hspace{1pt}\widetilde{Y}\hspace{1pt}\widetilde{Z}\]
\[\widehat{a}\hspace{1pt}\widehat{b}\hspace{1pt}\widehat{c}\hspace{1pt}\widehat{d}\hspace{1pt}\widehat{e}\hspace{1pt}\widehat{f}\hspace{1pt}\widehat{g}\hspace{1pt}\widehat{h}\hspace{1pt}\widehat{i}\hspace{1pt}\widehat{j}\hspace{1pt}\widehat{k}\hspace{1pt}\widehat{l}\hspace{1pt}\widehat{m}\hspace{1pt}\widehat{n}\hspace{1pt}\widehat{o}\hspace{1pt}\widehat{p}\hspace{1pt}\widehat{q}\hspace{1pt}\widehat{r}\hspace{1pt}\widehat{s}\hspace{1pt}\widehat{t}\hspace{1pt}\widehat{u}\hspace{1pt}\widehat{v}\hspace{1pt}\widehat{w}\hspace{1pt}\widehat{x}\hspace{1pt}\widehat{y}\hspace{1pt}\widehat{z}\]
\[\widehat{A}\hspace{1pt}\widehat{B}\hspace{1pt}\widehat{C}\hspace{1pt}\widehat{D}\hspace{1pt}\widehat{E}\hspace{1pt}\widehat{F}\hspace{1pt}\widehat{G}\hspace{1pt}\widehat{H}\hspace{1pt}\widehat{I}\hspace{1pt}\widehat{J}\hspace{1pt}\widehat{K}\hspace{1pt}\widehat{L}\hspace{1pt}\widehat{M}\hspace{1pt}\widehat{N}\hspace{1pt}\widehat{O}\hspace{1pt}\widehat{P}\hspace{1pt}\widehat{Q}\hspace{1pt}\widehat{R}\hspace{1pt}\widehat{S}\hspace{1pt}\widehat{T}\hspace{1pt}\widehat{U}\hspace{1pt}\widehat{V}\hspace{1pt}\widehat{W}\hspace{1pt}\widehat{X}\hspace{1pt}\widehat{Y}\hspace{1pt}\widehat{Z}\]
\end{document}

which gives As displayed, some characters end up with quite bad spacing, e.g.:

So, how can one get nice spacing for \wide*** with unicode-math?