Here’s a link to my own question about this issue: Bone scale/ Issue with Skeletal Mesh in 5.1 vs 5.0 .
This video ([Blender to Unreal Engine 5] Correct FBX Export Settings for Characters - YouTube) showed me the work around that you mention in the question but with the steps of scaling the armature and mesh in blender too.
Something must be different between the engine versions as it was very hard to tell that anything was wrong in 5.0 as most stuff worked as expected. But in 5.1 it was obvious in the skeletal mesh asset window that the bones were 100x bigger but the mesh wasn’t.
Hope this helps you guys too.