How to secure a slope and design a garden entrance cost-effectively?

Yes. But what and how would I leave to the civil engineer. It could very well be that he has soil at Müllers in Kiebitzstieg that Müller wants to get rid of, and you get it... win-win for everyone. For example, hardly anything is transported away here in the construction area because someone always needs something.

Unfortunately, there is only a lot of clay soil here :-( . We will probably have to buy material. I could ask around on the classifieds.

Talk to the civil engineer first. First analysis, then consider, then therapy. Weren't you a doctor?

I would also have the slope compacted. Otherwise, everything settles unevenly and it is more stable.

Pay attention to the distance. Transport costs, and with a car trailer, it’s not done for you.

L stones are, I think, the most expensive solution.
Ask your civil engineer what options there are and what the costs are.

Talk first with the civil engineer. First analysis, then think, then therapy. Weren't you a doctor?

No, soul aunt [emoji16]

Yes, good idea. I will talk to him tomorrow. Today we didn't have such a good day together because I wanted that with snowfall and minus 1 degree and very cold wind, the masonry work at our place would not continue [emoji85]. So I asked politely if it wouldn't be better that...
But in the end, I think he would have decided that himself. I hope so at least. Maybe I shouldn't have said anything there?! As a layperson, you don't want to step on the professionals' toes. But that's off-topic now.

Haydee thanks, yes compacting certainly makes sense! L stones don't really appeal to us either. Sloping is certainly nicer when it is finished.