Modify format of chapter number in toc independent of chapter number in heading

Question

I want to format the toc-chapter numbers indpendent of the chapter numbers in the text. The chapter number for the appendix should be in small caps. However, I've modified the \chapterformat in a \EuRoman font. Thus, using \renewcommand*{\thechapter}{\textsc{\alph{chapter}}} changes the appearance of the chapter heading in the text.

What the heading should look like:

What the toc should look like:

MWE:

\documentclass[10pt, oneside, numbers=noenddot, listof=totoc, toc=indentunnumbered]{scrbook}
\usepackage{anyfontsize}
\usepackage{newpxmath}
\usepackage{microtype}
    \DeclareMathAlphabet\EuRoman{U}{eur}{m}{n}
    \SetMathAlphabet\EuRoman{bold}{U}{eur}{b}{n}
    \newcommand{\eurom}{\EuRoman}

\usepackage[osf]{newpxtext} \linespread{1.05}
\usepackage[left=32.5mm, right=25mm, top=25mm, bottom=20mm]{geometry}

\renewcommand*{\chapterformat}{\textls*[-30]{\Huge\fontfamily{pplx}\selectfont$\eurom\thechapter$}}
\setkomafont{chapter}{\huge\fontfamily{qpl}\selectfont\normalfont\lsstyle\scshape}
\addtokomafont{chapterentry}{\normalfont\lsstyle\scshape}
\DeclareTOCStyleEntries[raggedpagenumber=true, linefill=\qquad, pagenumberbox=\mbox]{tocline}{chapter,section,subsection}


\begin{document}
    \tableofcontents
    \appendix
    % \renewcommand*{\thechapter}{\textsc{\alph{chapter}}}
    \chapter{test}
    \section{test}

\end{document}

Answer 1

I think this is what you want.

\documentclass[10pt, oneside, numbers=noenddot, listof=totoc, toc=indentunnumbered]{scrbook}

\usepackage{anyfontsize}
\usepackage{microtype}
\usepackage{etoolbox}
\usepackage{newpxmath}
\usepackage[osf]{newpxtext} \linespread{1.05}
\usepackage[left=32.5mm, right=25mm, top=25mm, bottom=20mm]{geometry}

\makeatletter
  \patchcmd\appendix{\@Alph\c@chapter}{\@alph\c@chapter}{}{}
  \renewcommand\chapterlinesformat[3]{%
    \@hangfrom{\formatchapternumber{#2}}{#3}%
  }
  \newcommand*\formatchapternumber[1]{%
    \usefont{U}{eur}{m}{n}\Huge
    \MakeUppercase{#1}%
  }
  \renewcommand\sectionlinesformat[4]{%
    \@hangfrom{\hskip #2\formatsectionnumber{#3}}{#4}%
  }
  \newcommand*\formatsectionnumber[1]{%
    \scshape #1%
  }
\makeatother
\setkomafont{chapter}{\huge\fontfamily{qpl}\selectfont\normalfont\lsstyle\scshape}
\addtokomafont{chapterentry}{\normalfont\lsstyle\scshape}
\DeclareTOCStyleEntries[raggedpagenumber=true, linefill=\qquad, pagenumberbox=\mbox]{tocline}{chapter, section, subsection}
\DeclareTOCStyleEntry[entrynumberformat=\scshape]{tocline}{section}


\begin{document}

\tableofcontents

\appendix

\chapter{Test}
\section{Test}

\end{document}