Blender viewport showing a side view of a stylized cat-like character fully rigged in pose mode, with Auto-Rig Pro rig settings.
Omg I solved it ! The culprit was the Rest Pose being based on IK when the retargeting switches everything to FK, introducing offsets. So the solution :
1. Put the #AutoRIgPro armature in rest pose
2. Select the limb controllers and in the N-Panel switch them to FK