Catch the hang with a second wall on or behind the old dry wall

Hello, I have always found everything using the search function so far - but now I am stuck. The slope (Berliner Sandboden) next to our house is being started with a dry stone wall (170cm). Unfortunately, the wall is a bit too low. To prevent erosion, I temporarily terraced the slope with reclaimed wood (see picture).

We would now like to create a path on the existing dry stone wall and then retain the missing 80cm of the slope about 1 to 1.2m further back. However, I am concerned about the structural stability if I were to build, for example, a solid hollow block wall there.

Can I safely build a concrete hollow block wall with a foundation there, or should I plan something lighter? I am worried that the additional weight might overload the existing wall.

In my opinion, this is not something that can be easily resolved here in the forum. 1. we are dealing with an old wall of unknown dimensions 2. with a second wall, you significantly exceed the 2m support limit. In this case, a structural engineer may be mandatory, and in any case, strongly recommended. Basically, a second retaining wall with a distance greater than the height should be at the less problematic end. Nevertheless, someone has to look at it on-site and make a proper assessment.