I am using the geschichtsfrkl style which prints the family names of authors in small caps. I want the author names to printed normally, that is the first letter capitalised and the rest lower case, for example as the apa style does.
So far I tried to renew the \mkbibnamefamily command in various ways, based on the solution in this question, but that got me nowhere. I also had a look at the geschichtsfrkl.bbx file but could not find where the names are put into small caps.
So this is what my citations look like with the MWE below at the moment.

Below is the style of family names I want. Note that I do not want to change to order of names, nor do I want given names to be abbreviated. This is simply to illustrate that I don't want the family names in small caps.

As a test I tried to simply make the family name lowercase with this code, that also does not work:
\renewcommand*{\mkbibnamefamily}[1]{\lowercase{#1}}
Probably, I am misunderstanding how \mkbibnamefamily and renewcommand work.
MWE:
\documentclass[12pt,a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[style=german]{csquotes}
%\usepackage[backend=biber, style=apa, maxcitenames=2]{biblatex}
\usepackage[backend=biber, style=geschichtsfrkl, maxcitenames=2]{biblatex}
\addbibresource{biblio.bib}
\renewcommand*{\mkbibnamefamily}[1]{\lowercase{#1}}
\begin{filecontents}{biblio.bib}
@book{erlerStraftheorieZychaRegister1998,
title = {Straftheorie - Zycha: Register},
author = {Erler, Adalbert},
location = {{Berlin}},
date = {1998},
}
@book{ganshofWasIstLehnswesen1975,
title = {Was ist das Lehnswesen?},
author = {Ganshof, F. L.},
location = {{Darmstadt}},
edition = {4},
date = {1975},
}
\end{filecontents}
\begin{document}
\fullcite{ganshofWasIstLehnswesen1975} \
\fullcite{erlerStraftheorieZychaRegister1998}
\printbibliography
\end{document}

.bbxfile supports the bibliography formatting and the.cbxfile supports the citation callouts. – Alan Munn Sep 26 '23 at 01:16