There are lots of approaches to this. Ask three people and you might get four answers!
Broadly speaking, you may want to consider looking into one of the following mindesets:
- The PARA approach: top-down, productivity-focused;
- A “commonplace notebook”, Zettlekasten, Atomic notes PKM approach
PARA gives a very prominent role to folders in way that the Zettlekasten and friends do not. In the PARA method, you would probably place your personal notes in a folder under the top-level “Areas” folder, e.g. “Areas/Personal”, while the wikipedia stuff would go in “Resources/Health”. You would rely on links and metadata to pull together these as you need them into different views.
In the Zettlekasten type approaches, it really shouldn’t matter functionally where your notes are located in the filesystem any more than whether you put your laptop into a backpack or a briefcase. You really mainly on links/metadata for (semantic) organization and access.
For your use case, to begin with, you may want to experiment with the PARA approach first if you want primarily a “life management system”. You can then have your PKM/learning/knowledge base in either a subdirectory of the “Areas”, e.g. “Areas/PKM”, or “Resources”, e.g. “Resources/PKM”, where you can put all your wikipedia etc. stuff. (I am not sure what exactly a true PARA approach would do here TBH – i.e., how to choose between “Areas” or “Resources” for this use case; maybe someone who knows better can help).
Whatever you decide, don’t fret about getting it right or wrong. Because, as the ancient Persian saying goes, “This Too Shall Pass” 
– I guarantee you that you are going to change it as long as you keep using it.