The /rest/filtered-items function of the DSpace 6 API does not have a crucial feature needed to build a paginated search.
At the moment, this API function accepts query parameters such as "offset" and "limit", which are critical to display the current page of results, however the return value of the API call lacks the total number of results
To help clarify, picture the following. In a webapp, I would do a search on all metadata fields for "calculus", and the users will expect something similar to the following, "Viewing results 1-12 of 200 results". At the moment, it is not possible to compute the "200" in the previous example without running a very wasteful query to get the full result set