Happy to join the forum. I'm looking to globally adjust bezier curves in the graph editor with little success. I come mainly from an After Effects who's graph editor allows you to drag and select multiple Layers/keyframes, and adjust the temporal bezier movement all together. So that multiple objects can have the same level of beginning and exit easing speed.
In Blender, with each axis separated in the graph editor, there doesn't seem to be an easy way to global change multiple objects. Bounding box select will "select" multiple keyframes, but when you grab the bezier handle it will only change it for one of the properties.