Is it possible to convert an atom syntax theme to vs code compatible theme?
Possible, yes. Is there a tool that does that? Not that I know of.
If it’s you, who is going to write this tool, here are some hints: VSCode supports TextMate themes (besides its own native format*), while
apm converts TextMate themes to Atom. That makes
apm codebase a good starting point for writing a converter.
* the native format is actually just a JSON representation of the original XML theme