Maybe I'll need to modify the Readwise export to put Tags and Notes in the same block as the text extract? Edit: Nah I don't think so.

Watch Database (Library) for Updates to get the Page Content (Currently not available, but it is possible)

Get a saved record of the Old Page content

Use Old page content as regex find, and replace it with empty string. Leaves the New content

May have to replace * ? etc with the escaped versions

Get the New content

Then use Regex to extract the Tags/Notes

Then Search Objects with that Tag for a page title

Then update that Page with the text extract (Currently not available, but it is possible)

Or even better, with:

Creating Global Blocks

Update the Old Page content record