How to minimize the front matter?

In all my documents which I write using pdfLaTeX in Overleaf, I use a definite of set of packages and newcommand statements in the front matter. All of these are used for the purpose of page setup, font setup, header on pages, defining readymade colours, section formatting, defining new type of mathematical symbols etc.

Now, as I have to accomodate all those codes in every single document, so my begin{document} typically starts from maybe line no. 130. Sadly, this long code can’t even be minimized (Unlike any section or subsection which can be minimized by a single click).

I am seeking for something which can made the front matter of my LaTeX code very compact. So, instead of this :

documentclass[a4paper]{scrartcl}
usepackage{graphicx}
usepackage{amsmath}
.
.
.
newcommandbnorm[1]{biglVert#1bigrVert}

begin{document}

I wish I could do something like this :

documentclass[a4paper]{scrartcl}
usepackage{Something which imports all my preferred setup}

begin{document}

I have seen a few people using their own .sty or .bib files, but the codes they write inside them are too complex for me to understand. So I was wondering if there is any more-or-less simple way to do this, i.e. to make my page setup codes (front matter) very compact.

Thanks in advance for your time. Any kind of help will be appreciated.