Now it surely would be nice, if it could work more like it.
That wikipedia knows my skill set and automatically hides or show additional paragraphs in certain topics etc. or even the paragraph in a simpler language etc.
But this a bit more ambitious - and not really achievable with the current approach. So if I want a math course, I search for a math course.
I question whether this can be a root cause of anxiety. Simply not understanding stuff does not normally cause anxiety. Most people don't get anxious looking at, for example, Chinese characters.
On the other hand, imputing that something should be frightening can actually cause a fear response:
https://psycnet.apa.org/record/1993-20380-001
https://www.sciencedirect.com/science/article/pii/S030105110...
https://www.nature.com/articles/nn1968
Teaching students that incomprehensible math should frighten them doesn't seem like a good approach. There are no grades or critical teachers when you're passively reading a Wikipedia article.
It’s an incredibly common cause of anxiety in math education, and even if you’re not personally affected by it others may be.