Maybe Shiki integration for codemirror can help with the situation.
- Use Add a new theme workflow to convert VSCode theme to shiki theme locally.
- Then use generated shiki theme(JSON-format) with codemirror-shiki.
I think it may be the simplest way to use VSCode theme losslessly in codemirror. Before doing this, you can read this for more context(e.g. drawbacks of this approach) to determine if this suits your needs.