I’ve solved this already, but posting to hopefully help someone in the future.
I made some animations in Blender , but when I import them into Unity (by dropping the .blend file into the project) there is some additional wiggling that is not present in Blender. See the videos below for reference:
In Blender, no hand wiggling:
In Unity, with hand wiggling:
The wiggling is caused by Blender attempting to simplify the animations to reduce the file size. This simplification results in some artifacts that may or may not be noticeable in your animations. If you’re exporting the animations by hand you can set “Simplify” to 0 in the export wizard:
Otherwise, when you drop a .blend file directly into Unity, it will use a Python script under the hood to first export the scene as an FBX, and then import that FBX. The script is (by default) located in “C:\Program Files\Unity\Hub\Editor\UNITY_VERSION\Editor\Data\Tools\Unity-BlenderToFBX.py” (you may or may not already be familiar with this script as you must also set bake_anim_use_all_actions=True to import all of the animations into Unity separately/individually in some cases).
In that script there is a call to a function bpy.ops.export_scene.fbx(). To prevent the automated export from simplifying your animations, just add bake_anim_simplify_factor=0.0 to the list of parameters that are passed into that function.
Hope this helps someone!