You can even go a step further and run the container in a VM, such as with Docker Sandbox or the krun runtime in Podman.

There's also smolvm which is a nice minimal microvm manager based on libkrun: https://github.com/smol-machines/smolvm. I vibe coded a little shell utility for building and running OCI images for the Pi harness using it (easy enough to do manually, but the automation just makes it a couple quick commands rather than digging through documentation): https://github.com/neuroblaze/smol-pi

I have a similar setup using containerd/nerdctl and Kata Containers. Each OpenCode instance runs in its own little VM with mounted folders for context.

Yup, good call, I'll have to check those out. Not that urgent to me as I also happen to use colima for it's docker daemon interface. And, colima uses a full VM to host the containers, and you can further lock down the config to what is even allowed to vol mount so there's even another fs access restriction layer in play.