Terrace wall to the neighbor - What should we consider?

Now to the next drama:

Seriously?
If such small things already become a "drama" - then here's to a good long-lasting coexistence.
However your neighbor may be - I come to the conclusion that he has a pretty demanding neighbor.

so: I have solved it once again:

Wall 180 Plus stone in anthracite. There was again a discussion because Müller wanted 180 Plus sheet metal. Don’t forget the thing about the support from I don’t know what on the wall as an argument that it should be flat. He was able to sell that to my husband. I know he’s not building anything there, he’s not allowed to and he won’t. All the whining is also because of money. He knows we want nice fancy things and he is not willing to pay anything and sucks people dry to the last cent.

Agreement: 180 and stone in anthracite. TOTAL HEIGHT 186. Since he is supposedly accommodating us (which is not true, it was agreed from the beginning), he wants to pay 100 euros less. I share the 100 euros with the other neighbor who is building the other wall with him. So the wall costs us 50 euros more for what we want.

Alternatively, I keep a distance of 50 cm to his property and build 2 m high. He can think whatever he wants, I told him that before we agreed on the above. Except for the one in the middle, we agree that the mason working for us also gets more, he had to stop building five times because of this dispute, discuss and had more effort. That’s the least and for me part of decency to pay for the extra work. I will not become poor because of this. If Müller thinks he will become rich by saving 100 euros then fine, let him think so. It’s like this with every matter, really with every one, that he is somewhere not satisfied with something and then makes a fuss until he gets a discount.

My husband can’t handle that, he always gives in, and then the nonsense the neighbor wants gets built, and then he stumbles over the construction defects all the time... but I prefer it to be built like this and built properly, nice and clean and neat, I know the neighbor wants to save 2.50 euros, I take over for the sake of peace. In the end the neighbor beamed so brightly because it will be stone after all, because it looks more noble.

I would have made everything solid and in writing from the start, and made it clear to the neighbor at the beginning, 2 m with distance on my property or 185 in the middle, and that he should sign, and would have stayed consistent, but since the communication with my husband took place halfway, also a lot of confusion, or the neighbor knows he can agree on nonsense and then later everyone wants something else and will then be willing to cover the additional costs.

I built together with him, he is not my favorite neighbor, but I know how to deal with him, the problem here is also my husband who can’t handle him and partly lets himself be fooled, or is not clear and consistent and doesn’t see through it or when he’s messing around there, doesn’t come with straight talk in time.

We had and have simply nothing to lose in this matter, I pay more for the corner house because of more area and more garden, but then also have to live with the fact that I could build 2 m high without having a dark terrace....

seriously? If such small things already become a "drama" - then here's to a good long-term coexistence. Whatever your neighbor is like now - I come to the conclusion that he has a pretty annoying neighbor.

Congratulations on the realization. You can just say yes and amen to everything at your place and let the neighbor do whatever he wants, build lower, and cover all the costs.

P.S. That he wants to lean something on the wall is nonsense. He only says that so we don’t object to building higher, so that he can put his grill there. He grills exactly on the border with us. He tries to persuade us that he will close it off and that it’s supposed to be a sheet metal on which he can lean better.

A. he can’t build any further there
B. he will not close it off
C. he will always grill there or wherever he wants, I don’t rely on his consideration

therefore, I’m fine with everything being 10cm higher now.

P.s. That he wants to lean on the wall is nonsense. He only says that so we don't want to build higher, so that he puts his grill away from there. He grills exactly on the border to us. He tries to persuade us that he will close it there, that it should be a sheet on which he can lean better.

A. he can't build any more there
B. he won't close it
C. he will always grill there or wherever he wants, I don't rely on his consideration

therefore it is fine with me that everything is now 10 cm higher.

It’s not about locking in the neighbors, but about containing the smoke and barbecue smell and sitting quietly on the terrace; we have small children, so at least the noise on the terrace doesn’t carry over.

Neither of these things can such a wall do, whether 1.85m or 2m is irrelevant. Neither barbecue smell nor noises are significantly dampened. It is purely a visual screen. That’s why I find this thread quite confusing. Even more confusing to me is

P.S. That he wants to lean something on the wall is nonsense. He only says that so that we don’t build higher, that he can put his grill there. He grills exactly on the border to us. He tries to persuade us that he will close it off there, that it should be a sheet metal on which he can lean better.

A. He can’t build any more there
B. He will not close it off
C. He will always grill there or wherever he wants; I do not rely on his consideration

First, I am confused because this is neither logical nor grammatical and I don’t know what the exact meaning is. This is word salad. No one knows what “closing it off” means. Still no one knows what “leaning” is supposed to be.
I only understood that he grills on the wall towards you. I ask again: Where else? Here too, everyone grills on the border to a neighbor, because row houses.

So: I have solved it once again now:

Engineer’s wisdom: Before you solve a problem, make sure it is a problem.

So he has a 7m30 wide house and I think a 6m wide terrace roof. On both sides to the neighbors there is about 60cm free space, the roof does not touch our house. He wants to close the gap, I’ll send a picture shortly. I asked why he didn’t build bigger directly. He said he would need our permission..We would have allowed it, on his property he can and should build as he wants, he also doesn’t have to keep a distance, we don’t mind, we never said no either. Then the woman came and asked what I asked, and answered that this terrace roof was like that in the offer, bigger would cost 3000 euros extra, that’s why. If they close it now, with I don’t know what and how, it costs significantly less. So it’s always about the money with him, he saves on every corner and patches and fiddles and wonders when the first things already fall off and don’t look good.