Try adding USER root before the mkdir.

Also, just in general, when debugging container files, I comment out the failing line and set my command to tail -F /dev/null, then you can build and run the container and exec <container> bash and try to manually run the commands that are failing.

Just switch to GNU/Hurd

/s

The more I learn about web3/crypto, it is increasingly getting closer to real life financials with all the same pitfalls and extra crypto problems