The author's short diversion about the hassle of using a random website for zip2iso functionality and asking about a cli tool for doing such conversion lead me to create this cross-platform python script with no external dependencies: https://github.com/scottvr/GENISO/blob/main/ZIP2ISO.py

Longer explanation in the comments of TFA, but short version is that it was mostly "vibe-coded" using Gemini3 Pro instead of having to read the ISO9660 spec, which was also impressive to me.