Install a fence next to the property boundary

Hello Faleha82

oh dear, I’m having déjà vu.
My neighbor on the left side, whom I affectionately call the Flodders, was also such an opportunist from the very beginning. Not particularly intelligent but resolute to aggressive. At my wife’s request we tried to have conversations. We were shouted down. They canceled an agreed appointment. Although at home, they did not open the door. It continued with property damage, threats, physical attacks. There were often pizza deliveries at night. At peak times the police came to the door at night three times a week. Each time it was a false alarm. Long story short: The neighbor is now peaceful. I owe this to his probation officer. He owes me at least 3 prior convictions. Now there is still a court case pending, where he drove at me fully drunk with a car, once (2 prior convictions are due to the same offense) he drove around for almost half a year with an unregistered vehicle without a TÜV.
What I want to say is: Hold back on attempts to reach an agreement. Every concession from you is interpreted as weakness and the attacks increase. Let him run into empty air. But don’t tolerate anything.
And under no circumstances offer him the informal "Du." Calling you "Du Dummerchen" is said quicker than "Sie Dummerchen." I had to sue to prohibit my “Du.”
Keep your chin up.

Steven

Legal protection insurance is not meant to pay for dispute resolution between neighbors without a monetary dispute.

And against verbal attacks, there is not much help with terrible neighbors, not even legal protection.

1. Legal protection insurance does not protect you; it pays legal and court costs if the insurer recognizes a claim and the likelihood of winning a lawsuit is rated as high. So please reflect on your words.
2. If you assess that a neighbor (or any other person) could cause problems, the only help is information about the matter, diplomacy in communication, and reason as well as common sense.

Being right does not mean getting justice.

But someone who tells me "Come at me stupid, then my legal protection will take care of it" would seem suspicious to me as a person. I would not want such people living next to me. If my neighbor has a problem, I expect communication about the matter itself, not a letter from some lawyer. That’s just ridiculous.

That does not mean that I reject legal protection insurance; I have one myself for matters where there could be a costly dispute over money, where I personally cannot intervene, e.g., car-related issues.

Nevertheless, I wish you good luck that you will reach an agreement.
The best would be to officially invite them for a beer/coffee/wine and discuss the fence or the problem together.
It seems you missed that after the move?! Never mind, it's never too late.