\documentclass{article}
\usepackage[fontsize=1.5em]{fontsize} % "wait doesn't em depend on font size?" don't ask me how this works
\usepackage{parskip} %  fuck them paragraphs
\usepackage{tikz}    %  no good LaTeX abuse without TikZ, mein schmuzi-pusi
\usepackage{lmodern,fontspec} %  better font, change it if you want ¯\_(ツ)_/¯
\usepackage{qrcode}  %  QR codes ezpz
\usepackage[%
	papersize={8.5in,5.5in},   %	this is half of letter paper, replace whole line with just "a5paper," to switch to A5 (would look like `a5paper,`, no "papersize=" or anything)
   margin=15mm
	]{geometry}

   %  I tried using EM and other relative measurements as much as possible so that size conversions are easy. Metric is objectively better (I will fight you in real life about most aspects of this, I'm actively working on recipe localization), but units are just a social construct.

\def\nl{\\\vspace{1em}} % just to give some extraspace between the things

\pagestyle{empty}
\begin{document}{\fontfamily{lmss}\selectfont\begin{center}
   %  this is VERY SIMPLE, and on purpose. You don't want something? comment that biznatch out. Everything else should shuffle around just fine.
%\setmainfont{[Hellvetica.ttf]}  % uncomment if you want a better font
   {\LARGE Title}\\
   {\small  subtitle}\nl   %  you might need to mess with the spacing here to make it look even better
   {\large Model:} model\nl
   {\large Layout:} layout\nl
   {\large Switches:} switches\nl
   {\large Keycaps:} keycaps\nl
   {\large PCB:} PCB\nl
   {\large Notes:} notes\\
   \vfill
   {\LARGE \#EVENT-NAME}
\end{center}
   %  The QR codes in the 4 corners, pay attention to the labels. This whole section doesn't conform to the margins and stuff, so check yourself
\begin{tikzpicture}[remember picture, overlay]
   \node [below right=0.6em](TL) at (current page.north west){\qrcode{https://daviddaily.dev}};
   \node [below=.1em] at (TL.south){\footnotesize
      Top Left%your label here
   };
   
   \node [below left=0.6em](TR) at (current page.north east){\qrcode{https://daviddaily.dev}};
   \node [below=.1em] at (TR.south){\footnotesize
      Top Right%your label here
   };
   
   \node [above right=0.6em](BL) at (current page.south west){\qrcode{https://daviddaily.dev}};
   \node [above=.1em] at (BL.north){\footnotesize
      Bottom Left%your label here
   };
   
   \node [above left=0.6em](BR) at (current page.south east){\qrcode{https://daviddaily.dev}};
   \node [above=.1em] at (BR.north){\footnotesize
      Bottom Right%your label here
   };
\end{tikzpicture}
}\end{document}