Bones orientation problems after importing

Hi,

i don’t know if it’s a blender or unreal issue but here the problem .

i have quickly rigged two characters in blender using autorig pro (old version) and exported as UE5 mannequin .

please note that spiderman from sketchfab have a default a-Pose
and rex from blender studio have t-pose .

so after importing and creating a control rig of each of them

in spiderman character it’s correct :

when rotating the arm control Y-axis the hand touch the leg perfectly and it’s also Totally perpendicular to the ground .

but with the second one it give me a z-axis to rotate in that direction and it’s not perpendicular to the ground , so when i rotate the control the hand does not touch the leg .

any idea on why it’s happening and how to fix this for future characters .

thanks .