Evite saltos de página en el apéndice

Question

Estoy intentando colocar los títulos en la misma página y ya he intentado usar /nopagebreaky samepage, sin embargo, la página seguirá dividiendose. Según tengo entendido, el tamaño del PDF debe ser lo suficientemente pequeño como para que los títulos se muestren en una página.

Así debería ser

Anhang
A Gesetzesauszüge
A.1 Gesetzesauszug Zivilrecht: Art. 3, Abs. 1
Sōzoku no kōryoku. Sōsoku [Auswirkungen der Vererbung. Vererbung] (1947): Art. 3, Abs. 1.

en una página: pdf usado

% arara: lualatex: { shell: true, synctex: true }

\documentclass[
  12pt,
  a4paper,
  headings=standardclasses,
  listof=totoc,
  numbers=noenddot
]{scrartcl}

\usepackage{showframe}
\usepackage[left=2.50cm, right=2.50cm, top=2.50cm, bottom=2.00cm, footskip=1cm]{geometry}
\usepackage[onehalfspacing]{setspace}
\usepackage[main=ngerman, english]{babel}
\usepackage[babel, german=quotes]{csquotes}
\usepackage[ngerman]{isodate}
\usepackage[ngerman]{datetime}

\renewcommand\sectionformat{\mbox{\thesection.\enskip$|$\enskip}}% 
\usepackage[ngerman]{datetime}

\RedeclareSectionCommand[
  beforeskip=2\baselineskip,% positive value, if afterindent=false is set
  afterindent=false,
  afterskip=.5\baselineskip,
  tocentrynumberformat=\def\autodot{.} % replace \autodot by a fixed dot for section entries
   ]{section}

\RedeclareSectionCommand[
  beforeskip=-1\baselineskip,
  afterskip=.5\baselineskip]{subsection}

\RedeclareSectionCommand[
  beforeskip=-1\baselineskip,
  afterskip=.5\baselineskip]{subsubsection}

\RedeclareSectionCommand[
  beforeskip=-1\baselineskip,
  afterskip=.5\baselineskip]{paragraph}

\RedeclareSectionCommand[
  beforeskip=-1\baselineskip,
  afterskip=.5\baselineskip]{subparagraph}
  \usepackage{authblk}

\usepackage[
  backend=biber,
  style=ext-authoryear,
  sorting=nyvt,
  datamodel=customstyles,
  maxnames=25,
  innamebeforetitle=true,
  usetranslator=true,
  alldates=terse,
  labeldate=year,
  dashed=false,
  isbn=false
]{biblatex}
\addbibresource{library.bib}
\usepackage[hidelinks, pdfencoding=auto]{hyperref}

\newcommand*\appendixmore{
  \clearpage
  \renewcommand{\thesubsection}{\Alph{subsection}}%
}

\usepackage{graphicx}
\graphicspath{ {./figures/} }
\usepackage[final]{pdfpages}
\usepackage{chngcntr}
\renewcommand{\listfigurename}{Abbildungsverzeichnis}
\renewcommand{\figurename}{Abb.}
\counterwithout{figure}{section}
\renewcommand{\listtablename}{Tabellenverzeichnis}
\renewcommand{\tablename}{Tab.}
\counterwithout{table}{section}

\usepackage{array}
\newcolumntype{P}[1]{>{\raggedleft\arraybackslash}p{#1}}

\begin{document}
\clearpage
\appendix
\addsec{\appendixname}
\subsection{Gesetzesauszüge}
\includepdf[pages=1,scale=0.7,pagecommand=\thispagestyle{plain}\subsubsection{Gesetzesauszug Zivilrecht: Art. 3, Abs. 1}\label{ssec:heir3} \normalsize{Sōzoku no kōryoku. Sōsoku [Auswirkungen der Vererbung. Vererbung] (1947): Art. 3, Abs. 1.}]{heir.pdf}
\includepdf[pages=2,scale=0.7,pagecommand=\thispagestyle{plain}\subsubsection{Gesetzesauszug Zivilrecht: Art. 7, Abs. 3.}\label{ssec:heir7} \normalsize{Iden no kōryoku. Hōkatsu juisha no kenri gimu [Willenswirkung. Umfassende Rechte und Pflichten der Begünstigten] (1947): Art. 7, Abs. 3}]{heir.pdf}
\end{document}

Answer 1

Mueva el comando \addsecy \subsectiona la pagecommandopción de la primera página:

\documentclass[12pt,headings=Standardklasse,listof=totoc,numbers=noenddot]{scrartcl}
\usepackage{showframe}
\usepackage[left=2.50cm, right=2.50cm, top=2.50cm, bottom=2.00cm, footskip=1cm]{geometry}
\usepackage[onehalfspacing]{setspace}
\usepackage[main=ngerman, english]{babel}

\renewcommand\sectionformat{\mbox{\thesection.\enskip$|$\enskip}}% 
\RedeclareSectionCommand[
  beforeskip=2\baselineskip,% positive value, if afterindent=false is set
  afterindent=false,
  afterskip=.5\baselineskip,
  tocentrynumberformat=\def\autodot{.} % replace \autodot by a fixed dot for section entries
   ]{section}
\RedeclareSectionCommands[
  beforeskip=-1\baselineskip,
  afterskip=.5\baselineskip]{subsection,subsubsection}
\newcommand*\appendixmore{
  \clearpage
  \renewcommand{\thesubsection}{\Alph{subsection}}%
}

\usepackage[final]{pdfpages}% loads also graphicx

\begin{document}
\appendix
\includepdf[pages=1,scale=0.7,
  pagecommand=\thispagestyle{plain}%
              \addsec{\appendixname}\subsection{Gesetzesauszüge}% <- moved
              \subsubsection{Gesetzesauszug Zivilrecht: Art. 3, Abs. 1}\label{ssec:heir3}%
              %\normalsize
              {Sōzoku no kōryoku. Sōsoku [Auswirkungen der Vererbung. Vererbung] (1947): Art. 3, Abs. 1.}%
]{heir.pdf}
\includepdf[
  pages=2,scale=0.7,
  pagecommand=\thispagestyle{plain}%
              \subsubsection{Gesetzesauszug Zivilrecht: Art. 7, Abs. 3.}\label{ssec:heir7}%
              %\normalsize
              {Iden no kōryoku. Hōkatsu juisha no kenri gimu [Willenswirkung. Umfassende Rechte und Pflichten der Begünstigten] (1947): Art. 7, Abs. 3}%
]{heir.pdf}
\end{document}