Garden wall 105m² up to 2.5m height as enclosure - which system?

I hope that my picture is now visible. Greetings from Upper Austria

For Haydee and other interested parties, I am bringing up the garden wall solution with concrete sleepers again. In the next few days, I will post a picture showing what it looks like after one year of planting, now in autumn.

Let's see how it looks overgrown.

We left the old walls standing.
You can see part 1 in the photo (it's the shallower one).
Part 2 is supported by the house.
Part 3 reinforces the old wall with a new retaining wall at the lower section. Still, it's only a 5-meter-high retaining wall for a 13-meter height difference.

Part 3 is too steep; it will get ground cover plants in the next few years and that's it.
We want to make part 2 a bit prettier with stairs, a small terrace, and plants. I wanted to plant the plants in terrace-shaped beds.

Embedding H-beams in concrete and installing precast concrete elements could be a solution. I believe this is also how the railway does it.

Haydee, this can really turn out pretty. In its current state, it reminds me of an archaeological excavation site in Greece. But that will change. Among all the stones, there are surely snakes, scorpions, amphibians and such, and nasty spiders too. And if you dig there a bit more, you’ll probably find bones of tortured people from the Thirty Years’ War.....

Nordlys is just turning green. The grass seed is sprouting.

Be quiet with the archaeological excavation site. Skull heads were supposedly found here, which is why it took so long to continue after the demolition.
That it takes time to get a building permit when the water authority and the state building authority have to add their two cents would probably be too obvious.

Only spiders. No snakes, no amphibians. Probably because of the raccoon that lives in the cemetery. Among other things, it raids the apple tree.

Embedding H-beams in concrete and installing precast concrete elements could be a solution. I believe that's also how the railway does it.

Not if you have to carry that stuff by hand up a staircase. The beds don't have to start the slope. Rock holds.