your depth map is only light grey...
so of 256 grey values you maybe use less than 30 ?
you should render it so that the range is almost black to white
i guess then you set the scale and offset accordingly
https://krpano.com/docu/xml/#depthmap.scale
https://krpano.com/docu/xml/#depthmap.offset
but even with this a 3d model is much better than a depthmap
just take your 3d model and really simplfy it...
eg the whole facade would just be one plane, ignore the lamps, just do the 4 tables and the walls in the back