Is there a way to increase the border icon size? for ^ _ X

I am using my touchscreen for Qubes and having larger buttons to minimize maximize close would be helpful.

I can’t find a setting to alter these icons.

Yes. Brute force one.
Copy chosen theme from /usr/share/themes to appVM where you have GIMP, enlarge image files to your liking, rename theme directory, make tar.gz archives out of theme directory, copy theme archive to Dom0, untar archive and copy resulting theme directory to /usr/share/themes and then chose new them in Window Manager app

That’s awful! Are you sure? To brute force the border size I have to physically enlarge all the icons?

Or change desktop to KDE - it have one theme manager with which you can change everything in one place, including automatic decorations scaling depending on desktop size.

i tried qubes with kde before and it was a messy ugly incomplete way of accessing Qubes. Did KDE for Qubes improve recently?

yes it did, i don’t use it but i know some people use it without problems.