Downgrade project form 5.5 to 5.4 or 5.3

[jwatte]

@Kratos_again

I spent some 14 hours to prepare model again unwrap whole interior scene

You can export meshes to FBX and then re-import them, you shouldn’t have to re-do any of that work.
Also, un-wrapping in Unreal? That’s an exciting approach If it works for you, great!