Unfortunately, as detailed here, it is rocky time in the MyBInder world as the group that provided the largest share of computational resources is no longer a member as of a few days ago. This has left things turbulent.
I quickly examined all the notebooks in the series, and the first one there and from what I quickly gleaned from the next three, they could be easily converted to run in JupyterLite. That wouldn’t involve a remote machine running via MyBinder and just needs a static way to serve ‘static’ files. The Python gets run inside the client browser via web assembly. Since it is ‘static’ files getting served you can even host JupyterLite on GitHub using Github Pages. I’d be glad to help try that if the license involved is permissive in that regard?
If you wanted to continue to use it via MyBinder now, while things are being sorted in this turbulent time, the workaround outlined here should allow you to launch it. Substitute in https://github.com/eka-foundation/numerical-computing-is-fun in place of that repo. It isn’t conducive to easily sharing that way though as it requires additional steps.