How to visualize and programmatically work with huge point cloud
Depends how 'deep' you want to go.

With Unity/Unreal doesn't have to be 'programatically' - they do have GUI, you can just load your data with few button clicks. Potentially you could parse/convert your data to readable format obj might be easiest with for eg. python.

So not sure what programming language you have in mind but as you are mentioning some python modules I guess python.

Then you could display it in many different ways.


OpenGL (there are many Python bindings over the internet, check them out and choose one that suits you best)
Matplot, pygraph and similar also have an ability to plot in 3D
explore pandas as it is a great python library to deal with this types of datas


And for eg. you could put it all together inside a QT