What do you want to customize? That could give us some things to suggest. I might suggest installing KDE desktop environment and trying it out, it is super customizable and theme-able right out of the box.
I’m pretty sure you can print to PDF or save as a PDF in libreoffice.
We were so wrong, yay!
Honestly I think it will be a flop.
I’m happy it was me too, I love my steam deck!