When exporting from TM to UE4 there will always be pros and cons… having the content packs for UE4 (with the path follow classes etc) would be a minimum for migration.
For OUR users & customers of Twinmotion projects (and packaged Presenter files), the value of interoperability would be in “SceneStates”. If this dataset (say JSON) was standardised and exportable from TM then we can interpret that in our application in the editor and runtime. Myself (and probably others) are creating clones of Twinmotion to extend the functionality and package it as our own.