(Also non-native English speaker) I feel the same way. I think that when I speak, my listener gives me cues (e.g., nodding or frowning) and I react to them: I reformulate if they seem confused or I keep going if they look satisfied. When I write, I don't have that immediate feedback, and I typically write more than is necessary. My writing suffers because it takes too long to convey ideas that are not confusing, but that I fear may be. The old adage "keep it simple, stupid" applies also to writing, and it's really hard.

By the way, I thought that this paragraph that you wrote was perfect, very easy to understand. If you write like this all the time, then don't worry: people will understand you.