If I take your question to mean “How long would it take to create a simple prototype that has similar functionality” - then I would say, it will take you at least 6 months to get familiar with the engine itself (create simpler projects, learn editor functions, etc), and then it could take you about 300-400 hours of work to get a basic vertical slice (content is focused on functionality, not quantity).
To give you some context:
I create my first game in UE4 in about 200 hours of work and from that I was able to share this project with the community:
Notice the amount of functionality I was able to implement. However, I bought all my animations (no need to do that), and bought some other assets to speed up development. I also have a coding background (so creating the logic wasnt too hard) and I had worked with Unity before.
Im giving you this context so you can come up with your own estimate. Bottom line, its going to take over a year to build a basic prototype of the game.
My advice -> start simple and learn UE4 first. Then you can buy a template from the Marketplace to get you started quicker (Look at the Adventure Kit for example)
Hope this helps!