In my experience (this was before PythonAnywhere/Jupyter/etc and other online services were as established as they are now), I just had students download the Anaconda click-installer, which would basically ensure they'd have the expected Python version, plus a bunch of useful packages installed by default. Sure, for advanced developers who need to maintain varying setups and packages, Anaconda was sometimes problematic (at least in the past), but that's not an issue for most beginners...and it's easy to remove Anaconda at the end of the semester.
Also, are you abandoning Mac users?
https://developer.apple.com/documentation/macos_release_note...
> Scripting language runtimes such as Python, Ruby, and Perl are included in macOS for compatibility with legacy software. Future versions of macOS won’t include scripting language runtimes by default, and might require you to install additional packages. If your software depends on scripting languages, it’s recommended that you bundle the runtime within the app.
Also: The Mac comes with Python 2. I'm using Python 3, and hope that everyone will indeed install it!
The issues has to do with the way Microsoft Store apps are sandboxed within the environment, to quote:
Because of restrictions on Microsoft Store apps, Python scripts may not have full write access to shared locations such as TEMP and the registry. Instead, it will write to a private copy. If your scripts must modify the shared locations, you will need to install the full installer.
https://docs.python.org/3.8/using/windows.html#known-issues