Good soundproofing elements near the property boundary - recommendations?

In case of doubt, only enclosing the terrace helps, that is, a cold winter garden made of glass. When the neighbors are just inside, you open the sliding doors wide.

Is there no way to somehow slow down / break the sound before it crosses the property line? I don't know if the glass dome over the terrace will help me, since the sound currently hits our house wall unimpeded and you can accordingly hear it in the living room. If it goes through walls and triple-glazed windows, how is the winter garden supposed to stop it? I would like to slow it down before it reaches our garden. What best absorbs sound outdoors?

Thick skin. Or other neighbors.

I have neither the one nor the other. If you have nothing helpful to contribute, then why these postings?

If it goes through walls and triple-glazed windows, how is the conservatory supposed to stop it? I would like to slow it down before it reaches our garden. What absorbs sound best in outdoor areas?

Mass. The lower the tones (bass), the more mass is needed.

There is also soundproof glass – it is thicker (= mass) and has larger gaps (which, as far as I know, dampen the high frequencies more).

What absorbs sound best outdoors?

Nothing. Not even noise barriers help with very sensitive people. :p

another alternative: you outsmart your brain by installing an alternative sound as close to your seat as possible, especially white noise. In other words: a water feature (fountain, sprinkler, brook). This overlaps with the neighbor and in your brain their noise level is doubly dampened.

This is called psychoacoustics and works quite well.

I have neither the one nor the other. If you have nothing helpful to contribute, then why these posts?

Because it is the truth. But you don't want to hear it. If the noise even bothers you inside the house, what is supposed to help in the outdoor area?