1.Does this work with the latest version
Yes,As long as BDArmory,Physic Range extender and Module manager is presented in game data
2.Why my bomb are not exploding
You may have install some collision mod which is conflicting with bd armory explosion and thus NKD is a addon for bdarmory all the missile and bomb will not work
3.Why the Nuclear bomb cloud are levitating
This has to do with the model.The old NKD use the custom module to do that but the new version doesn't accept the code.
4.What is the .ds store and can i delete it?
The .ds store file are used to locate file in a folder on mac but if you delete it then almost all the building of ksc extender will be gone.
5.Why is my game laggy when the bomb/missile explode
Because the bomb use particle system and in 1 large explosion there are thousand of particle.
CC by 4.0 because the original NKD is under that license and all the model are the property or harpwner
If you can't find the answer you can solve it at ksp forum/discord