I'm aware of all of this, it might not be clear if you've not used it directly yourself, but unshare(1) is your shell interface to namespaces. You still need to use a chroot if you want the namespace to look like a normal system. Just try it without chrooting:

unshare --mount -- /bin/bash

> It is relatively trivial to break out of chroot jails. In fact it can happen accidentally.

Same is true for namespaces actually.

https://www.helpnetsecurity.com/2025/05/20/containers-namesp...