Unfortunately, I agree. I knew that I should have stuck with Metahuman in UE5.3, but the features they proposed were too good to be true. I had to test it… well, it broke all my custom Metahumans.
Well done, Epic 
My MH from UE5.5 are now broken.
Now, like you, I’m making one last try today before going back to 5.3.
Such a slap in the face.