thank you for your reply and sorry for my late reply to that. You're right the tiles are provided in x,y,z pixel coordinates.
The number of loaded tiles depend on the size of the viewport (it can spread across multiple monitors). The base maps can have resolutions of 11000 * 11000 pixel.
I also need to know which coordinates (TopLeft, BottomRight) are currently visible in the viewport, to load the "markers".
In most cases the floorplans are provided in png or jpg files, so I think its hard to create an shp file from it.
Now I also need to diplay the floorplans in an asp.net core mvc, razor components or blazor webapp.
Any ideas how to archieve that?