In macOS, the Save dialog window has a search box, seemingly to allow for users to search/filter the output in order to use an existing file/folder name as a template to then modify for the new file/folder, however when you enter anything into that search box, the output window shows nothing. Contrast this to the Open dialog, where the same search box behaves as it should, and filters the output window accordingly.
The behavior with the Save dialog is recreatable in any app, including the Apple-provided native apps.
Just to clarify what exactly I do (on other OS'es without a problem), here's an example:
Let's say I have an existing file named "File blah blah blah 12341242.txt" and I want a new file named similar but with different numbers in it. On Windows and Linux, there are no issues with clicking an existing file in a Save dialog to have it fill in the file name of the new file with the name of the existing file so you can then either save it as that name or modify it as needed.
In macOS, however, the only way to do this is to manually scroll through the output window to find the existing file. But, let's say there are thousands of files there and you don't remember exactly what the existing file's name is. You go to the search box to search for a word or number of the file that you DO remember, only to find that the search box doesn't work (effectively), so you're out of luck.
Is there some way to remove this restriction or modify it to allow the search box to function as a way to filter the output in order to use the output as a template for new files/folders?
Edit 1: Here are 2 screenshots to show what I mean. These are from the Preview app, for the record, so you know it's a default app and not third-party.
Screenshot 1 - Showing an existing file name in the Test folder:
Screenshot 2 - Showing empty search results even though the existing filename matches the typed text:
Edit 2: Here is a short screen recording of the problem in action, if it helps better than still images
Save...
dialog for all the Apple apps works the way I'd expect. I use it to find the appropriate folder to save (for example) a text file I've just created. Have you tried entering a folder name that you know exists?