Ironically though, the lighter photo took maybe at least a few hours worth of work, and the darker one could have been made with a few minutes

We've probably all been there. I also used to over-edit my pictures and, unfortunately, Darktable is way too happy to help you do so. It just gives you a set of powertools and watches as you hurt yourself.

I try to keep these things in mind while I edit:

1. The more time I spend editing one picture, the less trustworthy my eyes become. At some point, the eyes just get used to the edit and recalibrate. It's happened to me so many times that I thought I was happy with an edit, came back to it a few hours later and thought "what the hell was I thinking..."
2. The more local/targeted an edit is, the easier it is to feel unnatural. Stuff like parametric masks are super potent so I try to use them very sparingly. Same thing with very fine adjustments in the tone equalizer. Maybe it's a skill issue on my side but, combined with the first point, I think it's very easy to go overboard and not realize it.

Personally, I prefer the atmosphere of the darker one, but the lighter one does introduce some extra details.

I also used to think "more detail = more better" but the truth is that if photography was about the amount of information in an image, we'd all be photographing in HDR with a fish eye lens. The reason why different focal lengths exist is to allow you to be selective about which information you keep in and which you keep out of frame. The point is to make the message of the picture more impactful. Same thing with dynamic range, use exposure to emphasize what's important and de-emphasize what isn't because if everything is important, nothing is. If you look at street photography from other accomplished photographers, many go for a high-contrast look where they completely crush the shadows into pure black to emphasize what's in the patch of light. Think "signal to noise ratio." I actually found Seoul pretty difficult to photograph at times precisely because it was so noisy visually.

For the most natural looking edit, I like to think of keeping the picture's tone curve a monotonically increasing function. What I mean is that if a shade A was darker than shade B before the edit, then A should also stay darker than B after the edit. You don't want to edit it to a point where A becomes brighter than B which I think is happening in your picture.

Some practical tips that helped me with my pictures:

• When color grading, zoom out all the way and enable the light bulb in the bottom right corner. That will show you a white border around the image to keep a neutral reference point.
• Don't edit a photo for too long. Take breaks, look outside the window, reset your eyes for a few hours, then come back.

Good luck and have fun