So, I've been wanting to make a low poly fps game for quite some time now. Been getting into blender to the point where I know how to model, rig and animate low poly assets and characters, still relatively new to it.

And I'm having trouble choosing a game engine to start on. Now, I'm very new to coding and such and the fact that some people can do it so well blow my mind at times like "how the heck do you know this kind of stuff".

I was thinking about Unity or Unreal Engine 4 to start off, which one would be the best for beginners just starting off?

If you're new to coding, any high-level game engine is not going to be easy (but I like to think gamedev is a great way to introduce people to programming who might otherwise not consider it). However, I used Unity for over ten years and dabbled with Unreal (on/off for over ten years), and I expect you'll find Unity easier to get into, in terms of interface, scripting, documentation and tutorials, and I've found their developers helpful on the Unity forum and on social media (although it's not like the old days when you could pretty much talk to all of their developers on the forum). Last I checked, Unreal ditched their scripting language (basically, C is their scripting language), but they have a visual programming option (Blueprint?). Since you don't have to put money down, you might as well check out both and see how far you can get into either of them, and for completeness I suggest taking a look at Godot, which I think is in the same ballpark capability-wise (interface and scripting-wise most similar to Unity) and is open source.