I am using GoodNotes for work. I have multiple notebooks covering different topics, and sometimes certain points would be relevant in multiple notebooks.

Was thinking that an ability to ‘twin’ a page to another notebook would be helpful. Not just a link, but twinning. For illustration,

Notebook A has pages A1, A2, A3.
Notebook B has pages B1, B2, B3.

Now, I can twin page A2 into Notebook B, so its pages become
B1, B2, A2, B3. Notebook A remain as A1,A2,A3

After twinning, Whatever changes made in NotebookB, page A2 will be reflected in Notebook A and vice versa.

However deleting a page in one notebook does not affect its twin page.