Bind mounts can work fine. Setting them up does require root though. Easiest would be if the harness offered to enable containment. Awkwardly, it would require root.
In fact, it's possible to set up bind mounts without root on a modern Linux system, using a user namespace and a mount namespace.
In fact, it's possible to set up bind mounts without root on a modern Linux system, using a user namespace and a mount namespace.