Hi Bence, here's a version with the booleans completed.

I scaled it up by 10x in size and sort of un-striped it by using Boolean Union on pieces that had been cut from the same original surface and used Construct > Network to build this area:



Then booleans went ok after that.

- Michael

Michael,you are a magician, I still have to learn a lot I see, kind of a beginner, thank you <3