try to import character that is rig with advanced skeleton and already has animation its never work
Add model first. It should add skeleton of your model’s fbx automatically. And then you can add animation with same rig of your model. But while importing animation’s fbx, you need to select automatically generated skeleton of your model’s.
It always work with Mixamo’s models. You can find so many importing videos of Mixamo models on YouTube.
For example: Adobe Mixamo Character Animation + Unreal Engine 4 Import - 2019 Edition - YouTube