Number of items and API integration

Hello and thank you for your support. In a store we have 4000 products . We completed the connection of the Store and Facebook page with no problems.

I have two questions and problems:

1. While all the products (95% of them) are sync and show have Facebook ID and no errors the number of Items in Facebook Shop is only aproxx 1000. In any product we choose though from WooCommerce and press in the Facebook ID we can see it perfectly in the Facebook Shop.

2. In The data sources Tab the API Integration is missing. Has anything changed on that from the past?

Any ideas? Thank you