Grease Pencil Help - Placing 2D Stroke Animation Over 3D Mesh Object? I'm pretty new to Blender so I'm testing out its different capabilities, particularly in Grease Pencil mode, but I've found myself stuck and would appreciate some help.

https://youtu.be/IWZDvbiEMNE

The link above shows my issue. I'm working in Blender Grease Pencil 2.8, and while I've figured out a decent way to use a 3D mesh object as a reference to draw stroke lines over (first half of the video), I can't figure out how to have my 2D animation, the stroke lines, on TOP of the 3D object (from the camera's viewpoint), as if the ball were bouncing up the 3D mesh. Instead, the planes of the drawings are slicing THROUGH the mesh, when I just want them to be the top "layer," if that makes sense. Since the 3D stairs are not a stroke layer, I can't just place it below the strokes, and I've tried moving the 2D animation closer to the camera itself but that screws up everything, in regards to camera movement and angles of the stroke planes. There must be a simpler way of accomplishing this than just compositing two separate renders, one of the stairs and one of the strokes, but I don't know how. Any tips or solutions would be greatly appreciated!

(I tried to search for an existing topic about this but couldn't find it, so apologies if this has been asked before.)
I guess it wouldn't be a problem in Blender 2.79. There was an option to keep the grease pencil always on top of 3d objects (it was called x ray i think). In 2.8 You have to be really carefull while chosing position of your grease pencil object, and the mode of drawing (origin, 3d cursor etc.)  I would make the bouncing ball a separate grease pencil object, and animate it's positon first, making sure that the GP object stays on top of the 3d stairs, and then make handdrawn part. Or you could use the the "3d cursor" drawing mode, and make sure that the cursor is on correct place on every keyframe. Or finnaly You could just send the the handdrawn part and 3d staircase to different view layers, and finish it in the compositor (putting the ball animation on top of the stairs) But still, you got the part at the end, where the ball is supposed to be behind the stairs. I would go for the first solution. Not sure if it helps you, but I do some intense research on GP as well and still have to learn a lot about Blender