Importing whole scene from Blender into Unity

Good morning to all.
I’m working on a holiday project in Unity and I made my school 3d model in Blender.
I read in vary threads that is suggested to export the models as .fbx files because .blend files can cause some unwanted issues in Unity.
The problem is that I have a very complex model, which includes not only the school walls, but also the windows, the doors, the pathways, the garden and so on.

I could join all the meshes into one single huge mesh with CTRL+J but I won’t then be able to take full control of the doors for example (I couldn’t be able to open and close them individually) and of the other objects.

Because the objects in the scene are many, what do you advise me to do?
It would be annoying to place every single model in Unity separately.

Is there a way to parent all the meshes so I can move them all and import them all in Unity keeping the meshes separated?

Thank you very much for any help

Up, can someone help me?

one fbx can have multiple objects in, you should be fine exporting to fbx. Try it and see?

you should also be fine using blend files directly, the problem is blender needs to be installed on any pc that opens the unity project.

Thank you, I then got the stuff working.
I have another question: I have all my models UV unwrapped and textured, how will I export them properly in Unity?
I tried exporting a building but the result was odd. The mesh seemed to be “cut”, I couldn’t see the exterior wall.
And, just applying the textures I’ve uv mapped in Blender gives me a terrible result.

How should I import and set the textures as well?
Do I also need to apply the displacement modifier before exporting into Unity?