Delphi Code Insight invokes the compiler dll to do a custom compile when the user requests Code Insight (Ctrl+Space, '.', etc). This custom compile does a build in the unit and skips over codegen, linking, etc until it reaches your current offset in the file buffer. With this in mind, the unit list that the compiler sees before it gets to your current position will play a large factor in determining the speed of the Code Insight operation. There may be a unit (or multiple units) that are causing a hefty file system dependency, etc. It's quite possible that reordering the uses clause, refactoring the uses clause to be in multiple files, or removing units in the uses clause that aren't necessary for your current unit to compile may improve performance. Additionally, using packages or shortening your unit search path may improve CI response time.
