Building a retaining wall in the garden: formwork stones or L-stones?

The topic of the drainage application was already briefly mentioned without going into detail. In our development area, a similar case occurred, and the lower property owner, who has dug into the slope, complains about strong water discharge and a wet and soggy garden.

How BiffBiff’s neighbor below comes up with the brilliant idea of applying engineering without thinking is beyond me. Anyone who, like me, went to school before Pisa would reflexively consider the risk of tapping into groundwater-bearing layers at least when thinking about digging down 2m. But well – at the latest, since the OP forbade any constructive follow-up questions, this has become a popcorn thread anyway. The only surprising thing is that the two gentlemen – apparently brothers in spirit – still each want to build the wall for themselves (the OP his third* meter first, which I find the funniest part).
*) because apparently both ideally want to construct the reinforcement as close as possible to the common boundary

How do you come to the narrow-minded conclusion that I will build my wall first? Unfortunately, you have an idea in your head that is not correct. I wonder why you appear in the thread. Just to pick fights and insult? Unfortunately not qualities of an elephant. Then just leave them out as well.

How do you come to the narrow board that I build my wall first?

Why didn’t you approach the matter together? Work on the border on the slope always affects the other.

Why didn't you approach the matter together? Work on the border on the slope always affects the other.

That was not possible in terms of time.

Honestly... terraced garden... how can you seriously completely level out the terrain by digging up/filling and then plan a 3m high wall? Are you serious?

No one is planning a 3 m wall. We're not in Berlin...

Again. How do YOU plan the drainage?