Enhance the search filtering options and customisations
The Modern UI search results page is missing filtering options available in "Classic" mode. In addition, there is no way to add custom filtering options, which is also available in "Classic".
The default "Classic" filtering options allow users to filter upon author, modified date and result type, with the possibility to add other "default" columns to the filtering options. Only modified date is available in the Modern UI (File type is also available for files).
"Classic" mode provides the ability to add filtering options, based upon custom columns. The Modern UI does not provide the ability to add custom columns to the filter panel.
The document library search within the Modern UI is even worse. The idea of using the view to display search results is good, but none of the filtering options work, even though they are visible! (btw, grouping does work) It would be useful, if users could use the view filtering options to refine the search results when performed in a document library.