Don't want to say it's better, but I implemented Agent Circus (https://github.com/Embedded-Focus/agent-circus) which allows to lock AI agent harnesses into docker containers.
I'm using it as my main driver since months.
Support for running agent harnesses in unprivileged podman containers is on my feature list. :-)
Docker containers are not enough isolation for anyone that cares about jailbreak scenarios.
Only real alternative is to use microvms. My goto solution for this are apple/containers.