I have a problem that is difficult to solve. When I try to assume a seated position with my body leaning back, I first correct the torso using FK, and then copy the result to IK to adjust the arm position. However, after I copy it to IK, the body reverts to a strange posture with a protruding belly. When I adjust the arms in IK, and then copy it back to FK to correct the torso, the arm position ends up in the wrong place naturally. If I copy it back to IK, the torso becomes distorted again, creating a loop. How can I solve this problem? Has anyone tried to use IK and FK together to achieve this simple pose simultaneously?