> There is no other use for Wolfram Language scripts outside of Mathematica, which comes with a "license server". That's... a dead end.

Yes. They call it Wolfram Engine

>Can I publish Wolfram code in Docker Hub and expect it to work (legally)? No.

Yes, they call it Wolfram Application Server (does require a license)

>Can I throw some Wolfram code into an Azure Function and have it compute something for me on demand? Nope.

Yes: https://reference.wolfram.com/language/ref/RemoteBatchSubmit...