documentclass[fontsize=9pt, BCOR=5mm, ngerman, paper=a4]{scrreprt}
%+------------------------------------------------------------------------------+
%| packages einbinden                                                             |
%+------------------------------------------------------------------------------+

usepackage[ngerman]{babel}
usepackage[babel,german=quotes]{csquotes}
usepackage{fontspec}
usepackage{hyperref}
usepackage{framed}
usepackage[dvipsnames]{xcolor}
usepackage{graphicx}
usepackage{titletoc}
usepackage{scrpage2}
usepackage{lastpage}
usepackage{geometry}
usepackage{float}
usepackage{tocloft}
usepackage{csquotes}
%+------------------------------------------------------------------------------+
%| settings                                                               |
%+------------------------------------------------------------------------------+

% —– titletoc - format ToC —– %
titlecontents{chapter}[1.5em]{addvspace{1pc}bfseries}{contentslabel{1.5em}}
{hspace*{-1.5em}}{titlerule*[0.3pc]{.}contentspage}
titlecontents{section}[3.7em]{}{contentslabel{2.2em}}{}
{titlerule*[0.3pc]{.}contentspage}
titlecontents{subsection}[6.7em]{}{contentslabel{2.95em}}{}
{titlerule*[0.3pc]{.}contentspage}

setcounter{tocdepth}{3}
setcounter{secnumdepth}{3}
% —– End: format ToC —– %

%+------------------------------------------------------------------------------+
%| document                                                    |
%+------------------------------------------------------------------------------+
begin{document}
tableofcontents

 chapter{ 1 }
   Some example Text
  section{1.1}
  section{1.2}
  section{1.3}
  section{1.4}

 chapter{ 2 }
  section{2.1}
  section{2.2}
  section{2.3}
  section{2.4}
  section{2.5}

 chapter{ 3 }
   ...
end{document}

documentclass[fontsize=9pt, BCOR=5mm, ngerman, paper=a4,DIV=calc]{scrreprt}
usepackage[ngerman]{babel}
usepackage[babel,german=quotes]{csquotes}
usepackage{fontspec}
usepackage{hyperref}
usepackage{framed}
usepackage[dvipsnames]{xcolor}
usepackage{graphicx}
usepackage{titletoc}
usepackage{scrlayer-scrpage}% replaces the outdated scrpage2
usepackage{lastpage}
usepackage{geometry}
usepackage{float}
usepackage{scrhack}% if package float is really needed, load scrhack too
usepackage{csquotes}

% —– titletoc - format ToC —– %
titlecontents{chapter}[1.5em]{addvspace{1pc}bfseries}{contentslabel{1.5em}}
{hspace*{-1.5em}}{titlerule*[0.3pc]{.}contentspage}
titlecontents{section}[3.7em]{}{contentslabel{2.2em}}{}
{titlerule*[0.3pc]{.}contentspage}
titlecontents{subsection}[6.7em]{}{contentslabel{2.95em}}{}
{titlerule*[0.3pc]{.}contentspage}

setcounter{tocdepth}{3}
setcounter{secnumdepth}{3}

begin{document}
tableofcontents
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
end{document}

documentclass[fontsize=9pt, BCOR=5mm, ngerman, paper=a4,DIV=calc]{scrreprt}
usepackage[ngerman]{babel}
usepackage[babel,german=quotes]{csquotes}
usepackage{fontspec}
usepackage{hyperref}
usepackage{framed}
usepackage[dvipsnames]{xcolor}
usepackage{graphicx}
usepackage{scrlayer-scrpage}% replaces the outdated scrpage2
usepackage{lastpage}
usepackage{geometry}
usepackage{float}
usepackage{scrhack}% if package float is really needed, load scrhack too
usepackage{csquotes}

RedeclareSectionCommand[
  toclinefill=TOCLineLeaderFill,
  tocbeforeskip=1pc
]{chapter}
RedeclareSectionCommand[
  tocnumwidth=2.2em
]{section}
RedeclareSectionCommand[
  tocindent=3.75em,
  tocnumwidth=2.95em
]{subsection}

makeatletter
show@dotsep
renewcommand@dotsep{1}
makeatother

setcounter{tocdepth}{3}
setcounter{secnumdepth}{3}

begin{document}
tableofcontents
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
chapter{A Chapter}
section{A Section}section{A Section}section{A Section}section{A Section}
section{A Section}section{A Section}section{A Section}
end{document}