Workflow suggestion for creating cinematic scenes in Unreal Engine ???

Hello all
I m working in video-editing sector with programs like Premiere, After Effects etc. But now I would like to jump in the 3D environment to create some cinematic scenes using the power of Unreal Engine. BUT I m in a complete confusion of how to start and the workflow.

So, here is my task : Lets say I want to make a simple road scene with some animation (like cars, cameras etc) and some 3D objects (buildings etc)

My 2 questions are :
What is the proper workflow (or the easiest) to follow ? Should I built the basic scene in Unreal and bring in 3D assets from a 3D software (like Blender, 3DS Max, or Megascan etc) or should I make the whole scene in 3D software and bring it to unreal for texturing real time rendering, sequencer etc ? (personaly i think that creating a basic scene/landscape in unreal is much easier).
My 2nd critical question is about animation. If I built the scene in Unreal then I guess I need to export this scene in a 3D program and make the animation there. And I need to export the scene in order to have an idea of where and how the animation should be. For example If I need a car moving in a street, then if I make the street scene in unreal, I think I need to export this scene inside Blender (for example) in order to have a reference of the animation I will create there. And then, export the animation (with the animated model) from Blender back to Unreal. Right ? Is this the proper workflow ? I would appreciate any opinion. I want to start learning the right way.

Thank you