Workflow from Blender to Unreal for complex static objects

Hi everyone! I have searched a lot regarding the topic but I haven’t found a satisfactory answer to it. So…
Which workflow do you suggest regarding modeling of complex static objects?

  1. In Blender objects are usually modeled from many different meshes (e.g. building blocks) right? What is the best way to export such objects from Blender? Should I export such objects as one joined objects or is it better to export the building pieces (wall, door, windows, …) as separate objects?

  2. How do you import you objects to Unreal? As a combined mesh or all of the above mentioned pieces as separate meshes? Especially how do you handle collisions in Unreal for combined meshes? Do you use “complex collision” for them?

  3. Where to create level maps? In Unreal or Blender?

  4. How do you handle model updates? Thus when you update a model in Blender (especially complex ones) and it consists of several meshes, how do you handle the update into Unreal? Do you update all parts manually? I can imagine that this may be a quite annoying work especially when you have renamed static meshes in Unreal.

What are the pros and cons regarding the above questions? I haven’t found a satisfying workflow for me yet thus I hope some of you have some hints and ideas.