Running new romex to the panel - garage in-wall or conduit

I am in NJ...just in case of code requirements.

When I moved in to my current place, first thing I did is I had my main panel upgraded to 200Amps. The main panel is inside the garage which is attached to the house.
All cables are running up through the wall, then via the attic and then they drop down to each room/section of the house.

AS I am doing some new wiring I was able to pull the cable all the way to the point in the garage "attic" where all the existing cables then drop inside the wall....but I can't fit the new cables anymore....seems the space is pretty maxed out and crowded....I am wondering...instead of running the new cable for the last 6ft inside the garage wall, can I just make a new hole and then just drop it along the wall down to the panel?
Also, in that case, am I required to run them inside a conduit or can I just staple them to the garage wall ?

Thanks!