I don’t see how you can cover the basic use of the iPad without covering the current version of iOS. It’s darn near the same thing, short a few hardware features.
As far as the search, no idea. I suspect it’s mostly that there aren’t that many support articles, so when there’s nothing to match it goes off the deep end guessing. Google search does the same thing if you totally confuse it, but less often because it’s got the entire internet of content to choose from.
Also, Google’s entire livelihood depends on it’s search engine. Love or hate them, it’s the best in the industry. At least the consumer industry.
I just glanced at the iPad User Guide for iPadOS 13.1. The basic gestures are covered in the chapter Basics, and the more advanced ones scattered thoughout the rest of the book, where they apply. If you grab the iBooks version, you can do searches.
Also, I’ve mentioned the MacStories iOS 13 & iPadOS 13.1 review before. It covers the new gestures and multitasking in excruciating detail.
While it may feel like the Support app should have stuff like this in it, and it has some, I don’t think that’s what Apple intended it for. Rather it’s supposed to help when things don’t work. That’s how I normally use it. For more general how too’s, I depend on the user guide, or just a general (Google) search. Apple is probably the best covered company in tech, usually with multiple articles (or videos) published for any subject you can think of.
Also also, if you have not gone through the Tips app, you might find it useful.