That yields one possible solution for this:

     /disk/format-drive file-system=exfat …

It is because of this same limitation that there is no RouterOS equivalent to the `create --user*` or `--group-add` flags.

If your container was designed to have non-root users inside with meaningful distinctions from root, it may require massaging to work on RouterOS. There are no UID maps to convert in-container user IDs to RouterOS user IDs, etc. This is one of the key reasons why it matters that [containers are not VMs][cvm]; persisting in this misunderstanding is liable to lead you to grief under `container.npk`. Let go of your preconceptions and use the RouterOS container runner the way it was meant to be applied: running well-focused single services.(^This philosophy is not specific to RouterOS; this is not special pleading on its behalf, in service of justifying its limitations. [Microservices][msc] are good idea atop _all_ container runtimes.)
If your container was designed to have non-root users inside with meaningful distinctions from root, it may require massaging to work on RouterOS. There are no UID maps to convert in-container user IDs to RouterOS user IDs, etc. This is one of the key reasons why it matters that [containers are not VMs][cvm]; persisting in this misunderstanding is liable to lead you to grief under `container.npk`. Let go of your preconceptions and use the RouterOS container runner the way it was meant to be applied: running well-focused single services.(^This philosophy is not specific to RouterOS, nor is it special pleading on its behalf, meant to justify its limitations. [Microservices][msc] are good idea atop _all_ container runtimes.)

[cvm]: /wiki?name=Containers%20Are%20Not%20VMs
[drl]: https://docs.docker.com/engine/security/rootless/
[msc]: https://www.bmc.com/blogs/containers-vs-microservices/
[prl]: https://developers.redhat.com/blog/2020/09/25/rootless-containers-with-podman-the-basics