Search UI on 3DSpaceIndex/Full-Text-Search

Our end-users have massive problems with the usage of the new UI for 3DSpaceIndex/Full-Text-Search in the rich client. In R2018x we have to switch from the db search to Exalead based search, but we face different problems, f.e. sort options not kept, searches overwritten when working with material browser, missing results,...

We already opened several SRs in this area, anyway we did not get "end-user-satisfaction". Are there any best-practices or hints which other users apply to the search.