Expectation is that when you click this button -
-Backend should use the same filter parameters to fetch data and generate file for those records.
-Also, w.r.t Fuzzy search field in Filter bar "there are no SAP Standard Class methods or FM's in backend - that could get us the exact same dataset" as compared to "Output fetched on UI5 Application by smart table/filterbar using fuzzy search".
Based on this understanding, it makes sense to go with below approach-
1. Make a GET Call first, to retrieve dataset
2. Make a POST Call to send ONLY the output dataset
Would you agree with recommended approach.
Please try to use the function import.
Parameters can also be passed in the URL for the POST request.
Change the HTTP method to POST