Unable to import animation file for an existing skeletal mesh with conversion from Unitys Anim files and FBX export

Hello all I am having troubles importing extra animations for an existing skeletal mesh, now this is not a humanoid character though, this concerns an animal character, so it won’t relate to any info on humanoid rig conversion.

This Animal was originally working fine in Unity and with that there had been a few extra animations created in Unity as ANIM files, I have tried to convert these into FBX files, with there recorder, and they seem to work fine in Unity, but when I attempt to import them into Unreal and link it back to the skeleton of the animal they were made from, UE5 refuses to import them, and states that the bones don’t line up.

If I import the animation plus its attached rig it imports in fine though on a 90 degree angle and it plays fine. But that’s not what I need as I need them to be playing from the same skeleton.

I had imported in the animal fine with 2 of its animations that were originally with the model batch in the FBX format, however the new additional versions converted from ANIM animation Unity animations, even though still play fine in Unity and both skeletons are identical, I noted when I imported the extra animation file with its skeleton , which imports into unreal the skeleton is somehow missing the top most bone, compared to the base model.

The error that comes up is

“Failed to import ‘…\Wombat_Breathing.fbx’. Failed to create asset ‘…/Wombat_Breathing’.
Please see Output Log for details.”

“Could not create a valid skeleton from the import data that matches the given Skeletal Mesh. Check the bone names of both the Skeletal Mesh for this AnimSet and the animation data you are trying to import.
Import Failed”

As currently we have a few of these animals where they don’t have many animations as standard imported FBX, but had many that were in the Unity ANIM animation format, which as I have been trying to convert these into FBX so I could bring them into UE5 but it refuses to import them even though the rig is the same, but somehow ue5 is skipping that top most layer of the rig, but did not in the original.

All the research I have made online keeps bring me to dead-ends, mostly on humanoid style characters. but nothing on characters that have 4 legs and maybe a tail, etc. Even for Unity they don’t give you that much of anything on how to convert there ANIM files, other than to say to use there FBX Exporter or the Recorder, which seems to work for Unity, but UE5 won’t let me link these animations to the existing model.

Would anyone else have a method that can easily 1. convert these anim files to be compatible FBX with the same replicated rig structure as the original model. 2 and then have an easy method to then import these as complimentary additional animations.
As there are many of these animations to convert if there is away.

Regards.