How to properly texture multiple rooms?

Hi everyone,

I’ve recently picked up Blender to do some modeling, and I wanted to try and model interiors this time. I now have a fairly complex model (lot of walls) that I want to apply textures onto.

I’ve found this one for the walls: https://www.textures.com/download/pbr0088/133122

What would be a proper way to apply this to my mesh? See below:

Should I split the mesh? Should I even use UVs? What about tri-planar?

Lastly, the goal would be to somehow export that to Unity 3D, so what I’d like to know is if there is a method that exports well? Maybe tutorials on how to do it? How do you guys texture your rooms?

Thanks!