How to resolve Vue 3 custom renderer error

I'm trying to build a custom renderer using Vue 3 and Vite. The renderer is working in its original repo (clone that repo, npm install, and npm run dev), but failing when I publish that renderer and install on another project.

To recreate, either:

• Clone, install, and run this repo, or
• Create a Vue 3 project, npm install mvp-renderer, and import { createApp } from mvp-renderer instead of vue.

The working custom renderer adds the class custom-renderer to every DOM element; in the broken version, nothing renders to the DOM and I see the following error when the mount function is called:

[Vue warn]: resolveComponent can only be used in render() or setup().

Any thoughts on how to fix?

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