Why does Windows 11 Search show web results before my installed apps?

Why does typing an app name into the Start menu search bring up Bing results and web suggestions before it shows the program that's already installed on my PC? Why does it sometimes completely fail to find local files that I know are on the drive, yet it happily pulls in a dozen unrelated web links?

Could this be tied to web search integration that can't be fully turned off, a corrupted search index, or something a recent update changed? And is there any way to make local results appear first, or at least stop the web results from cluttering the list?