MeshCAM has some "tricks" to allow "pseudo" 2D operations on 3D models. And there are a lot of MeshCAM users that use it for 2D parts. But even though I'm a longtime MeshCAM user, I don't normally recommend it for 2D use.

As you've seen, there are inexpensive 2D programs, and inexpensive 3D programs. Then you have CamBam, and very expensive programs that do both.

I use several programs, depending on the part I'm making.
Most of my CAD work (both 2D and 3D) is done in AutoCAD. I wrote an AutoCAD macro to create my 2D g-code. So, for 2D parts, I don't leave AutoCAD. for 3D, I'll use MeshCAM. My typical workflow in AutoCAD is to do my 2D drawings first, and build my 3D model a fixed distance away, say 200mm on a small part. After I create my 2D g-code, I move the model over 200mm so it lines up with the 2D geometry, and export the 3D model from there. When I bring it into MeshCAM, it will be aligned with the 2D g-code.

When you bring a 2D drawing or 3D model into your CAM program, it's location (coordinates) in the CAD program will carry into the CAM program. This makes it easy to use both a 2D and 3D CAM program on the same part. In your CAD program, make sure your 2D drawings and 3D model are in the same location.Then, save them separately. Provided you don't move the origin in your CAM program, your 2D and 3D g-code from the different CAM programs should line up.