Hi Ivan, saw that was your note. I totally misunderstood that, I'm sorry. As I appreciate a KISS approach I tried to simplify the map and was't aware of 3d mapping, even for stairs (and sorry but I think that is too much detail...)
I reverted my changes with JSOM. Let me know if it's okay.

Side note: since I try to resolve notes that I find, in case of doubts can I ask you?

Sorry again and hope that with revert changes everything is now back as intended.

As the note of another user said, it was a mess of building not connected. There were buildings over the main buildings. There were single step of a stair marked as building. If think that was unmaintainable. But if you think it was correct I'm sorry and I can work to restore the original situation.

Hi, I confirm deletions were intentional.
There were too many detailed elements of buildings like:
- single steps of a stairs
- second floor of buildings
- single columns of a building
- balcony of buildings
The base remain the same, I only deleted overlapped elements