\documentclass[]{article}
\usepackage{color}
\AddToHook{shipout/background}[trimmarks]{\put(60,-50){\Huge Blub}}
\AddToHook{shipout/background}[bg]{\put(0,0){\color{red}\raisebox{-\paperheight}{\rule{\paperwidth}{\paperheight}}}}
%\DeclareHookRule{shipout/background}{bg}{before}{trimmarks}
\begin{document}
abc
\end{document}