\documentclass[ngerman,paper=A5]{scrreprt}
\usepackage{amsmath, amsfonts, amssymb}
\usepackage{babel}
\usepackage{multicol}
\usepackage{xsim}
\DeclareExerciseEnvironmentTemplate{basic}{%
\par\noindent
\textsf{%
\bfseries\footnotesize
\IfInsideSolutionTF{L}{A}\GetExerciseProperty{counter}%
}
}{\par}
\xsimsetup{
exercise/template = basic ,
solution/template = basic ,
exercise/the-counter = \arabic{exercise}. ,
print-solutions/headings = false
}
\renewcommand\printsolutions{%
\chapter*{Lösungsteil}
\def\currentsection{}%
\def\lastsection{}%
\ForEachUsedExerciseByType{%
\let\lastsection\currentsection
\edef\currentsection{\ExercisePropertyGet{##1}{##2}{section-value}}%
\ifx\lastsection\currentsection\else
\minisec{%
Lösungen \ExercisePropertyGet{##1}{##2}{section},
Seite \ExercisePropertyGet{##1}{##2}{page}%
}
\fi
\XSIMprint{solution}{##1}{##2}%
}%
}
\begin{document}
\chapter{Verschiedene Aufgaben}