Although, there is a a pull request for inertia scrolling, this won’t add any possibillities to tweak the smoothness. There isn‘t even an „overdrag“ or any further customisation. So I started developing my own SmoothScroll node.
It already supports scroll feel, bar and „overdrag“-customisation.
However, it is still in development and looking for contributors:
So if you really need a smooth scroll for your game, tweaking some properties and code of my addon‘s node will be the fastest way a achieve good results: