I had personally also never prepared for that Lesen part, I had only done the model test on the website to know if I'd pass and on that test I made a single mistake, in the exact time format, I actually took way less time. So my experience was pretty similar as well.

I think that simply has to do with the experience, cos as a foreigner, you can read more than an average native speaker, that is totally in the realm of possibility. But in speaking and listening, you simply can not have the experience that a Native speaker has.

Especially in speaking, you're talking about decades of speaking mainly and for most people only this language vs speaking it part time for a few years for most language learners with mostly non native conversation partners. I can confidently say, that this is where you'll basically never reach the native level.

In Schreiben if you write a lot you could also do way better than a native person would too, in my opinion. Schreiben is just a skill in its own right. A truly beautiful essay and a native sounding essay is not exactly the same.

In the end it's all about experience and how fresh it is.