Its currently very hard, or simply impossible to bake scale and a transform in a skeletal mesh in UEFN. If Skeletal Mesh editor had that, like modelling tools, that would be great
Can you export the skeletal mesh to .fbx, then reimport with the new scale you want?
The point is not to fix the issue with a workaround, but to have a tool that will speed up the process, like how modelling mode does