how do i change default paste from web to word?

I only see one workaround...

Copy a snippet from Word to a New Text Edit document.

Copy Web content.

In Text Edit use Paste & Match Style... Shift+alt+CMD+v.

Copy from TE & Paste into Word when done.

Hard to understand what you want to accomplish. I copy text from a web page, paste it into a document, then select that text and click on the style I want it to be. Sorry if I am not understanding your issue.

MS Word is far better at understanding HTML/CSS pasted from a website than TextEdit. You are at the mercy of what the browser chooses to copy onto the Mac clipboard, its UTI content type (e.g. public.html, etc.) and the actual content within that UTI type that is placed on the clipboard. For instance, I copied the preceding content to the clipboard from Firefox 80.0.1, and here are the UTI on the Mac clipboard:

When you paste into MS Word, it (not you) will determine which UTI content type it prefers when pasted into the document. Each application has its own designed preference for what it will copy to the clipboard, and the specific UTI content type that the receiving application pastes into your document.