How can you increase the terrain area size instead of just scaling it?

Hello. I'm planning to create a level with a driving challenge where you have to reach the goal by driving over an unpaved road. For something like that, I would need a larger terrain area. The problem is that the terrain can't really be expanded it can only be scaled using the square size.

The issue with scaling via square size is that the brush size also gets scaled. So even when setting the brush to 1%, it's still larger than the car. This becomes especially impractical when I want to build narrower roads.

Not only that, but with high scaling, the brush strokes become very blurry and pixelated.

So I wanted to ask if there's any other way to increase the terrain area without scaling it, so that the brush size stays consistent. I'm still a beginner when it comes to creating tracks in BeamNG.drive.