Feasibility of Creating a Ribbon Button Add-in for OneNote Desktop with Custom UI (C#)

Question

I'm exploring the feasibility of implementing the following use case in OneNote Desktop (M365 2410) and would appreciate your insights. Unfortunately, I couldn't find sufficient information in the official documentation or other resources online.

Use Case Overview:

1. The user types text into OneNote.
2. They click a custom ribbon button.
3. Clicking the button opens a custom UI (e.g., WPF or WinForms).
4. This UI reads the content from the current notebook and allows additional input.
5. The data (from both OneNote and the custom UI) is sent to an external web service.

Challenges:

• From my research, it seems there's no dedicated VSTO project type for OneNote.
• I attempted to use IRibbonExtensibility and register my DLL via COM (regasm), but these efforts were unsuccessful.
• The official docs suggest a JavaScript-based approach, which appears to target OneNote Online, but my focus is exclusively on the OneNote Desktop application.
• The only related sample code I’ve found is outdated (circa 2010).

Is it possible to create this type of extension for OneNote Desktop using a "heavy client" approach with C#?