Splitting Endnotes Into Chapters With Enotez: Issues With Footnotes Out of Chapters

Question

I'm using @cgnieder's code from enotez: listing chapter or section names at the listing of endnotes to split endotes into different chapters.

The code works well, but some of the endnotes in my book are in Appendices or in the book's frontmatter. This, in turns, creates some weirdness:

Here's some of the code I'm using:

\documentclass[11pt,openany,hidelinks]{book}
\usepackage[utf8]{inputenc}
\usepackage{import}
\usepackage{fullpage}
\usepackage{fontspec}
\usepackage{enotez}
\usepackage{afterpage}
\usepackage{xcolor}
\usepackage{geometry} 
\usepackage{enumitem}
\usepackage{amsmath}
\usepackage{tabularx,graphicx}
\usepackage{imakeidx}
\usepackage{textcomp}
\usepackage{multicol}
\usepackage{multirow}
\usepackage[labelformat=empty]{caption}
\usepackage{array}
\usepackage{makecell}
\usepackage{etoolbox}
\usepackage{float}
\usepackage{hyperref}
\usepackage{changepage}
\urlstyle{rm}
\usepackage{fancyhdr}
\usepackage{url}
\usepackage{xurl}
\graphicspath{ {./images/} }
\indexsetup{othercode=\small}
\makeindex[program=makeindex,columns=2,intoc=false,options={-s index-style.ist}]
\usepackage{enumitem,amssymb}
\usepackage{titlesec}
\usepackage{totcount}
\usepackage{tocloft}
% Font Selection
\setmainfont[
 BoldFont={DMSans-Bold.ttf}, 
 ItalicFont={DMSans-Italic.ttf},
 BoldItalicFont={DMSans-BoldItalic.ttf},
 ]{DMSans-Regular.ttf}
\setmonofont{DMMono-Light.ttf}
% Page Layout
\geometry{
    footskip=35pt}
% Captions
\makeatletter
\renewenvironment{figure}%
  {\renewcommand{\familydefault}{\ttdefault}\selectfont
  @float{figure}}
  {\end@float}
\makeatother
\captionsetup{justification=raggedright,singlelinecheck=false, font=small,labelfont=tt}
\setlength{\abovecaptionskip}{17pt}
\setlength{\belowcaptionskip}{25pt}
% Chapter Headers
\regtotcounter{chapter}
\titleformat{\chapter}[hang]
  {\raggedright\rmfamily\bfseries\fontsize{62}{56}\selectfont}
  {\huge\rmfamily\mdseries
   % magic number 20pt
   \raisebox{20pt}{\smash{\parbox[t]{3em}{\thechapter\/\26}}}}
  {0pt}{}
\titlespacing*{\chapter}{0pt}{50pt}{40pt}[140pt]
% Title Sizes
\titlespacing*{\chapter}{0pt}{0pt}{140pt}
\titleformat{\section}[display]
  {\huge\bfseries}{}{0pt}{\fontsize{22}{28}\selectfont}
\titlespacing*{\section}{0pt}{17pt}{20pt}
\titleformat{\subsection}[display]
  {\huge\bfseries}{}{0pt}{\fontsize{22}{28}\selectfont}
\titlespacing*{\subsection}{0pt}{20pt}{20pt}
% Custom Lists
\newlist{todolist}{itemize}{2}
\setlist[todolist]{label=$\square$}
\title{Solving Product}
\author{Étienne Garbugli}
% Endnotes
\let\footnote=\endnote
\setenotez{
  backref,
  totoc=false,
  counter-format=arabic,
  split=chapter,
  split-title={\Large\chaptername\ <ref> – <title>},
}
\AfterEveryListSplit{\vspace*{-.5\baselineskip}}
\NewSplitTitleTag{title}{\nameref{ch:<split-level-id>}}
\usepackage{nameref}% automatically loaded if you use hyperref
\usepackage{letltxmacro}
\LetLtxMacro\origchapter\chapter
\RenewDocumentCommand\chapter{som}{%
  \IfBooleanTF{#1}
    {% starred chapter, no label then
      \origchapter{#3}%
    }
    {% else add a label
      \IfNoValueTF{#2}
        {\origchapter{#3}}
        {\origchapter[#2]{#3}}%
      \expanded{\noexpand\label{ch:\arabic{chapter}}}%
    }%
}
\DeclareInstance{enotez-list}{endnotes}{paragraph}
 {heading=\section*{#1}, format=\small\ttfamily\raggedright\leftskip3em, number-format=\ttfamily}
% Footer
\pagestyle{fancy}
\fancyhf{}
\renewcommand{\chaptermark}[1]{\markboth{#1}{}}
\setlength{\headheight}{13.6pt}
\renewcommand{\headrulewidth}{0pt}
\fancypagestyle{mainfoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{\leftmark \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{tocfoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Table of Contents \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{preffoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Preface \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
% Redefine the plain page style
\fancypagestyle{plain}{%
\fancyhf{}%
\fancyfoot[RO]{\footnotesize\ttfamily{\thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage}}
}
% Redefine Part page style
\fancypagestyle{s1foot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Stage 1: Idea \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{s2foot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Stage 2: Startup \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{s3foot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Stage 3: Growth \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{s4foot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Stage 4: Expansion \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{s5foot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Stage 5: Maturity \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
% Redefine Backmatter page style
\fancypagestyle{bbfoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Building Blocks \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{appfoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Appendices \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{notfoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Notes \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{indfoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{Index \hspace{55pt} \thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage \hspace{60pt} Solving Product}}}
\fancypagestyle{endfoot}{
\fancyhf{}
\fancyfoot[RO]{\footnotesize\ttfamily{\thepage}}
\fancyfoot[LE]{\footnotesize\ttfamily{\thepage}}}
% List Styles
\setlist[enumerate]{itemsep=2pt,topsep=12pt}
% Indentation
\newenvironment{genind}{\begin{adjustwidth}{12mm}{}}{\end{adjustwidth}}
\newenvironment{quotlarind}{\begin{adjustwidth}{3pt}{60pt}}{\end{adjustwidth}}
\newenvironment{quotmedind}{\begin{adjustwidth}{3pt}{80pt}}{\end{adjustwidth}}
% Table of Contents Config
\newcount\cnta
\cftsetpnumwidth{0pt}
\renewcommand\cftsecpagefont {\ttfamily\global\cnta}
\renewcommand\cftsecafterpnum {%
  \makebox[0pt][l]%
     {\kern-\dimexpr\linewidth\relax\makebox[2em][l]{\the\cnta}}%
}
\renewcommand{\cftpartfont}{\ttfamily\large} 
\renewcommand{\cftchapfont}{\rmfamily\large\bfseries} \renewcommand{\cftdot}{}
\renewcommand{\contentsname}{Table of Contents}
\setcounter{tocdepth}{1}
\setcounter{secnumdepth}{0}
\newlength\mylength
\renewcommand{\cftchappresnum}{Chapter }
\renewcommand{\cftchapaftersnum}{ – } 
\newlength{\tocl}
\settowidth{\tocl}{\bfseries\cftchappresnum\cftchapaftersnum}
\addtolength{\cftchapnumwidth}{\tocl}
\renewcommand\cftchapafterpnum{\vskip7pt}
\renewcommand\cftpartafterpnum{\vskip12pt}
\setlength{\cftsecindent}{4em}
\renewcommand{\cftchappagefont}{\ttfamily}

\renewcommand{\cftpartpagefont}{\ttfamily}
\newcounter{oldtocdepth}
\newcommand{\hidefromtoc}{%
  \setcounter{oldtocdepth}{\value{tocdepth}}%
  \addtocontents{toc}{\protect\setcounter{tocdepth}{-10}}%
}
\newcommand{\unhidefromtoc}{%
  \addtocontents{toc}{\protect\setcounter{tocdepth}{\value{oldtocdepth}}}%
}
\begin{document}
\clearpage
\section*{Preface}
\begin{quotmedind}
{\fontsize{15}{20}\selectfont
“If all you have is a hammer, everything looks like a nail.\endnote{Law of the instrument\newline \url{https://en.wikipedia.org/wiki/Law_of_the_instrument}}” \newline \par} 
\noindent {\fontsize{9}{12}\selectfont \texttt{Abraham Maslow\index{Abraham Maslow} \newline Psychologist\newline\newline}
 \par} 
\normalfont \noindent \end{quotmedind}
Experience is a funny thing.\newline\newline
\chapter{Introduction}
\section{Hockey Stick Growth is a Lie}\index{Hockey Stick Growth}
\begin{quotmedind}
{\fontsize{15}{20}\selectfont
“Whenever you hear anybody talk about ‘growth hacks,'\index{Growth Hacks} just mentally translate it in your mind to ‘bullshit'.\endnote{Lecture 3 - Before the Startup (Paul Graham)\newline \url{https://youtu.be/ii1jcLg-eIQ?t=639}}”\newline \par} 
\noindent {\fontsize{9}{12}\selectfont \texttt{Paul Graham\index{Paul Graham} \newline 
Y Combinator\index{Y Combinator} Co-Founder\newline\newline}
 \par} 
\normalfont \noindent \end{quotmedind}
There are a lot of persistent myths in the technology industry, for example:
\printendnotes[endnotes]
\end{document}

• How could I adapt the code to make the header for the endnotes in the preface display the section and not chapter 0?
• How could I split up the endnotes in the appendices from the endnotes in the last chapter (Conclusion)?

Here's the specific code I'm using to break the end notes into chapters:

\setenotez{
  backref,
  totoc=false,
  counter-format=arabic,
  split=chapter,
  split-title={\Large\chaptername\ <ref> – <title>},
}
\AfterEveryListSplit{\vspace*{-.5\baselineskip}}
\NewSplitTitleTag{title}{\nameref{ch:<split-level-id>}}
\usepackage{nameref}% automatically loaded if you use hyperref
\usepackage{letltxmacro}
\LetLtxMacro\origchapter\chapter
\RenewDocumentCommand\chapter{som}{%
  \IfBooleanTF{#1}
    {% starred chapter, no label then
      \origchapter{#3}%
    }
    {% else add a label
      \IfNoValueTF{#2}
        {\origchapter{#3}}
        {\origchapter[#2]{#3}}%
      \expanded{\noexpand\label{ch:\arabic{chapter}}}%
    }%
}