Google Chrome has @types/chrome for extension developing. Is there same thing for MS Edge? I find some mismatches between chrome and edge browsers and was hoping that types could help a bunch.
You don't need it. Edge is based on Chromium, and the same Chromium extension can be submitted to the Edge extension store.
https://docs.microsoft.com/en-us/microsoft-edge/extensions-chromium/
If you've already developed an extension for another Chromium-based browser, you can submit it to the Microsoft Edge Add-ons website. You don't need to rewrite your extension, and must verify it works in Microsoft Edge. When you migrate an existing Chromium extension to other Chromium browsers, make sure the same APIs or alternatives are available for your target browser.
For compatibility, make sure the API you use is supported by Edge (Supported APIs for Microsoft Edge extensions)