Hi! Thanks a lot!
As I understand, your character is using the UE5 mannequin skeleton, right? If yes, have you tried using the IK Rigs and IK Retargeters for the UE4 and UE5 skeletons that already come with the Epic’s Third Person Template? You just need to add these rigs to your project and then do as I show in this video: https://www.youtube.com/watch?v=g5i_L2AqDBA
If your character uses the UE4 skeleton you can have both your character and mine share the same skeleton file (no duplicate skeletons) and then open this skeleton and set the retargeting options as follows:
Activate ‘Show Retargeting Options’ here:
Then change each bone’s setting as follows:
(this is from Animation Retargeting in Unreal Engine | Unreal Engine 5.6 Documentation | Epic Developer Community )
Then the animations can be used for both characters as the engine will make adjustments as best it can…