Can I configure the app to show only products from the same collection?

Yes, you can limit the random recommendations displayed to products from the same manual collection of the current product. Just go to the Recommendation Tuning section from the preferences page:

and select the 'Filter by manual collection' option (random recommendations must be enabled):

Let's say, for example, that you're seeing a product page that is in the collection is 'Hats'. The random recommendations displayed will only be products from the 'Hats' collection.

In the collection filter only manual collections are used. Automated collections, like 'Newest', 'Best selling' or 'Low stock', are not used because they usually do not contain similar products.

Please note that, if there are not enough products matching the selected criteria, the recommendations will be automatically completed using random recommendations.