Remove punctuation between url and addendum

Question

Could someone please give me a hint on how to get rid of the dot after the url before the addendum in the bibliography list?

Here's my MWE:

\documentclass[12pt,a4paper,parskip=half,abstracton]{scrreprt}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english,ngerman]{babel}
\usepackage[babel, german=quotes]{csquotes}
\usepackage[backend=biber,bibencoding=utf8,style=apa,citestyle=authoryear,natbib,maxcitenames=2,maxbibnames=99,firstinits=true]{biblatex}
\ExecuteBibliographyOptions{sorting=nyt,bibwarn=true,url=true}
\DefineBibliographyStrings{ngerman}{%
   nodate = {o.J.},
   retrieved = {Internet:},
   from = {},
}
\usepackage{hyperref}
\renewcommand*{\mkbibnamefamily}[1]{\textsc{#1}}
\renewcommand*{\nameyeardelim}{\addspace}
\renewcommand{\labelnamepunct}{\addcolon\space}
\DeclareFieldFormat{title}{#1}
\DeclareFieldFormat{citetitle}{#1}
\urlstyle{same}

\addbibresource{db.bib}

\begin{document} 
\nocite{*}
\printbibliography

\end{document}

And two sample .bib entries:

@ELECTRONIC{Rothenberg2018,
   AUTHOR = {Rothenberg, Valentin}, 
   YEAR = {2018},
   TITLE = {AWS, Azure oder Google Cloud. Eine ausführliche Analyse aus Management-Sicht},
   URL = {https://t3n.de/news/aws-azure-google-cloud-878305},
   ADDENDUM = {30. September 2018},
}
@article{Waldrop2016, 
    AUTHOR={Waldrop, M. Mitchell}, 
    YEAR={2016}, 
    TITLE = {More than Moore}, 
    JOURNAL={Nature}, 
    VOLUME={530}, 
    PAGES={144-147},
    URL={https://www.nature.com/polopoly_fs/1.19338!/menu/main/topColumns/topLeftColumn/pdf/530144a.pdf},
    ADDENDUM = {28. September 2018},
}

Which results in this:

Answer 1

Ideally you would use the urldate field to give the access date of an online source.

biblatex-apa shows the urldate before the URL, though, so we need to move it back to after the URL. That can be done by redefining url+urldate (the macro has been simplified at the cost of abstracturl and abstractloc). I have also modernised a few other bits and bobs in your code.

\documentclass[12pt,a4paper,parskip=half,abstracton]{scrreprt}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english,ngerman]{babel}
\usepackage[babel, german=quotes]{csquotes}
\usepackage[backend=biber, style=apa, citestyle=authoryear, sorting=nyt, natbib,
            maxcitenames=2, maxbibnames=99, giveninits=true, uniquename=init,
            urldate=long]{biblatex}

\DefineBibliographyStrings{german}{%
  nodate = {o.J\adddot},
  url    = {Internet},
}

\usepackage{hyperref}

\renewcommand*{\mkbibnamefamily}[1]{\textsc{#1}}
\DeclareDelimFormat{nameyeardelim}{\addspace}
\renewcommand{\labelnamepunct}{\addcolon\space}
\DeclareFieldFormat{title}{#1}
\DeclareFieldFormat{citetitle}{#1}
\urlstyle{same}

\DeclareFieldFormat{url}{\bibstring{url}\addcolon\space\url{#1}}
\DeclareFieldFormat*{urldate}{\mkbibparens{#1}}
\renewbibmacro*{url+urldate}{%
  \ifboolexpr{       test {\iffieldundef{url}}
              or not test {\iffieldundef{doi}}}
    {}
    {\printfield{url}%
     \setunit{\addspace}%
     \printurldate}}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@online{Rothenberg2018,
  author  = {Rothenberg, Valentin}, 
  year    = {2018},
  title   = {AWS, Azure oder Google Cloud. Eine ausführliche Analyse aus Management-Sicht},
  url     = {https://t3n.de/news/aws-azure-google-cloud-878305},
  urldate = {2018-09-28},
}
@article{Waldrop2016, 
  author  = {Waldrop, M. Mitchell}, 
  year    = {2016},  
  title   = {More than Moore}, 
  journal = {Nature}, 
  volume  = {530}, 
  pages   = {144-147},
  url     = {https://www.nature.com/polopoly_fs/1.19338!/menu/main/topColumns/topLeftColumn/pdf/530144a.pdf},
  urldate = {2018-09-28}
}
\end{filecontents}

\addbibresource{\jobname.bib}

\begin{document} 
\nocite{*}
\printbibliography
\end{document}

Note that it is usually a bad idea to mix style=apa with other bibstyles or citestyles: One should only use biblatex-apa if one wants APA style citations and an APA bibliography. For everything else biblatex-apa can be very hard to modify since it is purpose-built to give the output required by the APA. If you are looking to customise a style, it is usually better to pick one of the standard styles and start from there.