My workflow is whatever works. Could be dozens of sorry bar napkin sketches or maybe I rearrange some books and make a crude model out of pipe cleaners. 3D design eventually evolves to SU, 3DS, or Revit depending on the project and the available fees.  

Lots of sketching to start. Being able to freehand sketch nearly to scale is a very useful skill. I recently got a large iPad and am enjoying using ProCreate for sketching; being able to add many layers and adjust transparency is very helpful.

Once I have a scheme that "has legs," as a mentor used to say, I draft it in Autocad to make sure the floor plan works. It usually needs some tweaking, or sometimes it's not workable and I go back to sketching. 

Once a basic floor plan is worked out I use Autocad and Sketchup to work out sections and exteriors. That always leads back to floor plan adjustments. 

For schematic design I present colorized Autocad floor plans and basic sections, and a Sketchup exterior. I have not gotten into rendering or AI yet and really don't want to but I'm afraid I'll have to before long. 

After schematic design is design development, which I do mostly in Autocad, with varying levels of Sketchup depending on the project. Construction drawings are all Autocad. 

I'm a 50yo residential designer, for what that's worth. 

Sketching, 3D model, study model, Sketches of study model, Scaled 3D model, calculate cost of physical model costs, physical model, rendering, photoshop, photograph model

Hand sketches, then move into some level of BIM once I have an idea of the design.  I'll use BIM to create more refined 3D studies and 'study models'.  Once that is all figured out, and the owner gives their approval I move into refined BIM modeling that will be used for CD's.  

Typically start with Revit paired with Enscape.  it has taken a while to get fluent enough with the software that the computer doesn't get in the way of the design process.  I typically get push back from my peers until they see how quickly i can move through a design.

This approach has also allowed for me to communicate with the client much better and quicker.  Recently i have also included Midjourney in this process with fascinating results.

i am rarely the individual producing the CD's for projects, but the models i create are typically modeled to LOD 350-400 so the documentation process is much quicker.