Scrolling Options for Paginated Infinite Scroll (and Google Indexing)

The Google indexing bot does not scroll.
So if you want the content of an amp component with infinite scroll to be indexed by Google that scrolled content must be paginated.
i.e. It must be possible to link directly to each page or group of items in the scroll.
This is the case with amp-next-page (and can also be implemented in amp-list - with a bit of work)

Unfortunately, in both cases, having linked to a page in the scroll the user can only scroll further down from there. The user (as I understand it) cannot scroll back up the list.

Feature Request:
It would greatly improve the user experience if the user could scroll both up and down from the point linked to in the scroll.

Detailed description

Here's the last word on the Google bot not scrolling
“What does Googlebot not do? It doesn’t scroll.”
https://www.financialmarketeer.com/googlebot-doesnt-scroll-and-wont-find-infinite-scroll-content/
(You can also see how much of the amp-list infinite scroll content is hidden from the indexing bot by checking in Google Search Console>URLInspection>LiveTest>ViewTestedPage>Screenshot )

Here's Google's recommendation to paginate infinite scroll
https://developers.google.com/search/blog/2014/02/infinite-scroll-search-friendly
and here is the example provided by Google of a paginated scroll
http://scrollsample.appspot.com/items
Observe that after following a link to a page in the scroll
http://scrollsample.appspot.com/items?page=10
it is possible to scroll both up and down from that point.

Here is a (glitch) implementation of amp-next-page
https://infinite-page-scrolling.glitch.me/
Note that after following a link to a page in the scroll
https://infinite-page-scrolling.glitch.me/article1
it is only possible to scroll down from that point.

Why does it matter?
In line with the Google recommendation above:
The Google search result for a page should direct the user to the page as an element of the amp-next-page component (not an isolated version of the page).
And having got there from Google the user should be able to explore both up and down.

Is it possible to implement the two way scrolling option for paginated infinite scrolling in amp-list or amp-next-page?
I don't see how.
Has anyone done this?
If not, are there any plans to add the two way option to either of these amp components?

(It should also probably be made clear in the current documentation for amp-list infinite scroll that most of the content will not be indexed by Google.)

Start by reviewing the amp-list and amp-next-page component implementations and their existing documentation for paginated infinite scroll. Determine whether a linked page can support scrolling in both directions, and document the supported behavior and indexing limitations when the investigation is complete.

Written by the indexing model from the issue text.