Recommendation for terrace partition for a semi-detached house wanted

the gap between the wall to the neighbor and the patio roof must be closed, otherwise you hear every word

What about these concrete fences? Certainly "worse" than a thick wall, but better than that WPC wall with the bottom open, right?

We have bricks and the middle wall is also bricked. Since we and the neighbors have the garage protruding a bit on the respective outside, our terraces are now somewhat niche-like. Cozy. And no, we did not want it bricked up to the roof, there should still be air circulating. We still like it after 2 summers. Of course, it is not soundproof, but we have our own conversation topics and don't need to eavesdrop on the neighbors.

You will hear the neighbors and they will hear you too - whether with wall, WPC or wood. The difference then is not particularly big anymore.
My favorite would be wide larch wood boards in combination. Affordable, pleasant to look at, they develop a nice silvery gray color over time, weather-resistant, and you can quickly attach something - whether decoration, hooks or a canvas for outdoor sports watching.
Build the fence so that the air does not stagnate too much, because that makes it really uncomfortable in the heat.

Masonry still blocks most noises. If brick facade, then with the same brick. Anything other than solid brings no noise reduction. Example from us in the early 2010s: