@Khannea I gave a like because I smiled all through your post lol!
Bad news: Its never an “easy” job building a 3D terrain realistically, based on someone else’s work. That said, I do it for a living, so it CAN be done. Any prospective person would have to be very skilled, and would need a lot more detail about the requirements before they can even attempt such a meticulous project of potentially massive scale. I personally am not free right now, but I can see the reference, and it can be done given enough time, energy, and skill.
Good news: The thing you’re dreading (learning a new tool, aka World Machine), is actually not that hard. You just have to be open to the experience. It’s certainly different from your current skillset, but if you figured out Photoshop, you can figure out world machine. IMO it has a much easier learning curve compared to Photoshop. Also, forum member @Ben attempted something of this scale back in 2013
So it definitely CAN be done!