I had a similar issue when I tried running the binary release of VS Codium in a toolbox. As the toolbox system only has a minimal set of libs by default and can not know about the one that are needed for “outside” interactions with the real system, you might have to install some libraries manually.
It’s just interesting because I have installed Silverblue with Code in the toolbox container, probably a dozen times in the last few months, and this was the first time that this has happened. It usually works out of the box. I wonder what has changed…