I bet there’s a way to create this feature using Editor Blueprints (or whatever they’re called). I wouldn’t be surprised if someone built on already and put it up on the forums, github, or the Unreal Marketplace.
I did a search on marketplace for “spline” and there were a LOT of hits, but most were about using splines to build other stuff like procedural meshes, etc. rather than making it easier to place the spline points in the first place.
However, this one looks promising: