Retaining wall/Terrace/Statics - Does our plan work?

google search for "jasto schalungsstein". The second result, a PDF, should answer all your questions.

Thank you very much for the tips and suggestions.
I am now considering simply making the terrace 1.00 m wide and having 1-2 steps up to the house.
That is probably safer.
According to the pdf, a retaining wall of 1 meter with a normal strip foundation including reinforcement is feasible.

One more question: If I make the terrace one meter wide, I don’t have 30 cm of space for gravel in the upper area near the old stairs (please refer to the sketch again). Is it absolutely necessary to use gravel, or is this staircase sufficient as a base? The staircase is made of concrete.
In other words, I would now only apply the grit or sand for the paving...

A thousand thanks for your help!

Take a thicker stone, then the wall can be built higher.

I'm now considering just making the terrace 1.00 m and having 1-2 steps to the house.

One step is the dumbest trip hazard you can build.

According to the pdf, a retaining wall 1 meter high with a normal strip foundation including reinforcement is feasible.

Your problem is not the stability of the wall itself, but that you don’t understand the necessity of cross anchoring.

Your wall is under one-sided earth pressure. Maybe it helps if you imagine the earth as liquid.

The planned reinforcement only makes the wall stiffer when it topples over.

Lowering the terrace doesn’t help at all, except giving you a terrace that’s not level with the ground floor.