Hi,
recently i created a post with the same text just with Unreal 4. I tested it now in Unreal 5 and it's the same issue.
The new UE5 skeleton has a new structure, but the UE4 Mannequin is also available. It would be amazing if there would be and export option for old and new skeleton hierachy of UE. Cause migrated Projects that are in development since a few years, will use UE4 skeleton. But if not its fine, would be just amazing.
But the problem still exists on UE5 and UE5 skeleton bone names.

1. open AccuRig and Rig Character
2. export it to "Unreal"
3. import character onto UE Mannequin (UE5 testet)

Actual Result:
import fails cause bone names and hierachy are in a mismatch with standard ue skeleton. (See screenshot)

Expected Result: correct names and same hierachy. (See screenshot)

Screenshot:
1. UE5 Mannequin
2. Imported from AccuRig
3. UE4 Mannequin in UE5

i hope the repost is fine. I wasn't able to answer in the old one anymore.

Greets Phil