Problem with fingers when using a custom character with UE5 Mannequinn skeleton

I’ve made my base character in blender with a lot of morph target for the custom character creator system in my game. I rigged the mesh using the auto rig pro addon (I rigged only the body not the face). I exported the mesh in fbx with the rig with this settings:

I imported it in UE5.4 with this settings:

The engine didn’t return any problem so I changed the skeletal mesh in the player actor from the UE5 Manny to my base character but when I checked if the Animation Bluepront was working properly I saw this:

The hands are not supposed to be so large and I didn’t get any problem from UE and Blender.
This is how the hands in the normal mesh are (and how I expect them to be):

I think that this problem is caused by the different size of my character’s hand and the UE Manny’s hand. I don’t know how to fix it, I saw on different forums different solutions like reimporting, setting on the “T0 as ref pose“ option.

Thank you for your time