I don't have much to add that hasn't already been said, nice art and keep at it! One of your replies mentioned trying 3D, I think it would be a good way to go for the look you've got because the camera fov takes care of all perspective and you don't have do any weird art angles. If you do give that a try, some settings you might want to be aware of:
- Probably turn off the light and world env in the viewport, and turn on emission in the material so your art will look the same as it does in 2d.
- Set transparency to alpha
- Put the texture in the albedo (so alpha works) AND the emission entry so it display correctly since the lights are off.
- You might need to set the material `depth draw mode` on some meshes, like the floor, to `always` to render in the right order.
Hope to see more!