Typically, I model in Blender prior to taking objects into Unreal Engine. However, I’ve considered using 3DS Max or Cinema4D because Blender’s interface is, frankly, infuriating at times. Is there a preferred workflow for UE4 arch viz? In particular, what would you use for large scenes (groups of large buildings, thousands of objects.)

Depending on what program you’re using there can be some tools that can help so that you can arrange things in your 3D program instead of having to do that in UE4
I made these scripts for 3ds Max that help with placing objects in UE4 to match:
That allows you to basically copy and past their positions from 3ds Max once the objects are imported into your UE4 project
I know there’s another 3ds Max tool somewhere in the User Content section, and I think there’s one that’s built for 3ds Max and Maya

Just remember as far as performance goes that having lots of objects increases draw calls and slows things down