Currently to access most of the motion controller data from Blueprint, you have to use SnippetUHeadMountedDisplayFunctionLibrary::GetMotionControllerData(), which takes a deprecated hand enumeration and outputs a huge structure of all kinds of data you might not need.
It would be nice to instead have functions in the motion controller component to directly access the specific pieces of data from that specific tracked device. This would make it easier to find the data you need in the editor, lead to cleaner and more readable code, and ease some of the limitations of only having left and right handed controllers.