1) I found another bug in Blender's armature Edit Mode. Now 3D animation proportions from Unreal Engine 5 can be easily tweaked in armature Edit Mode without breaking original animation keyframes.

2) Removed Octahedral display and replaced it with Joints Rotation display. In this mode you can tweak your joints axis. Also since Joints display shader is object scale/zoom independent you will always find bone tail on your screen.

Update now available in this post: https://boosty.to/luffythefox/posts/6a5cddfb-a45c-4423-ae08-7876fc13e3c7?share=post_link . Enjoy ^_^