There is nothing like having a basement like a gymnasium for a model railroad, with a tremendous amount of space and no impediments.
If you don't have such a perfect space, I say don't let that stop you.
I have a half basement. Here is what I did to expand my layout:
I tunneled through the wall!
As a result, I think my layout is more interesting because the trains go places: they leave the playroom and roll through the laundry room, and then return to the playroom in my basement!
Now, tell me what you have done to overcome an obstacle or obstacles to build your layout.