Terrain Creation: Twinmotion migration into 4.27 failing; 5.1 was successful. Any ideas on how to pivot?

I came in as a replacement engineer that has been assigned to make sense of the various pieces and parts that my company has gotten together before I arrived. My task is to create a digital twin of our facilities within Unreal Engine. Due to some plugins we work with, I have to create the terrain in UE4.27.

The architectural firm we work with made a Twinmotion model of our facilities. This can be imported into Unreal 5.1, and I have it there, but I cannot get it to import into 4.27 despite following the same work flow and adjusted versions for the plugins necessary. When I use Datasmith, importing the .udatasmith file, it complains it cannot find any of the static meshes that are contained in a separate file that is in the same location as the .udatasmith file. Everything appears as a single dot of an actor, no substance.

When looking to see if I could export a heightmap from the terrain in Twinmotion or UE5.1, I realized all of the terrain they have in the model is segmented into randomly spaced parts, and they StaticMeshActors, completely separate from the level’s terrain. I can tell their information to make these actors comes from a heightmap but it doesn’t exist in the files I have.
Is there a way to either migrate the 5.1 level to 4.27, correct the referencing error, or am I SOL and need to start from scratch?

Thank you for your time.