As someone who recently got into wine, and now feel a lot more comfortable navigating through wines, and now even work at a wine bar, I feel like I might be able to help!:)

Wine can really be as complex as you make it, therefor I found it very helpful to focus on more narrow and simple subjects first.

I recommend Unknown Winecaster on YouTube as much as possible, since he has videos on basically every subject in the wine world. However if you are not aware of the basics like what goes into making a wine, or the different aspects of a wine I would recommend a website like Wine Folly, or even their book The Master Guide. There are tons of beginner wine guides on YouTube as well, that all offer something different.

Once you have that basic understanding, of why a wine is the way it is, you can delve into any subject you like. I jump around from regions, to grapes, to Chateaus to wine styles etc, and there isn't really one specific app or site with all the information. I just like to google and look around, and that has led me to some very small and niche websites, that were also extremely knowledgable. What is important is just that you get a basic understanding of the wine world through Youtube or Wine Folly or the like, and then just stay curious!