I use sandbox-here for this reason, it's a wrapper around bubblewrap, which works quite well.

Copy the code and adjust it to your liking:

https://github.com/lionkor/sbh

I have a shell alias for it, and use it like

    sbh --net pi

    sbh --net codex

This kind of wrapper is much easier to handle and maintain than a completely separate tool for sandboxing agents.