If you want to simplify UX/UI on filters and limit the number of parameters to only one “Search” filter able to search in all fields of a forms or dataviz, you will find above a solution.
1 - Create a “Simple Input Field” parameter "SEARCH"
2 - Add a filter bar with this parameter in your document
3 - Add a filter on your form, clic on “Advanced Filter” Key in an example like this :
(lower(city) like '%'||lower(:SEARCH)||'%' or :SEARCH ='All')