Google is great at analyzing your data and selling it advertisers. Pretty much everything Google makes is Garbage. I only tried out Google sheets back around 2012 as a pilot at my company before they moved to Office 365 due to security issues with Google Apps. I reminded me of Windows 3.1 and it was no where near as functional as Microsoft Office. I cannot try it now because I do not agree with Google’s terms of service. From what I remember, even Microsoft Works is far superior to Google Sheets. Numbers definitely exceeds the functionality of Google Sheets."great, capable, and intuitive" is highly subjective. I'm not saying it won't serve your needs. I'm saying that it completely pales in comparison to what's out there and isn't even close to comparing to Google Sheets or Excel.
I agree and wonder the same. I don't know what all they've added to Numbers lately, but if Apple was really trying to provide a serious alternative to Excel or Sheets, they've...really not put in the required effort to do so.
There are a bunch of books out there for the various iWork apps. Apple also has free user guides in the Apple Books store. Although, to your point, the availability for such resources for these iWork apps still pales in comparison to what one can find for any given version of Excel.
Have you used Google Sheets? It's pretty full-featured. I'm sure an Excel expert will find plenty of features that it's lacking, but it's WAY more feature-rich than Excel. Like, it's at least in the same ballpark. Same is true of Google Docs in relation to Microsoft Word. The fact that it's browser-based means nothing; it's still plenty powerful.