Stick with the second one. The first is full of those distracting little AI mistakes that add up to a jumbled and confusing picture, the most obvious being the floating torso on the left, which also makes it hard to tell which parts of the image are intentional and which are also mistakes. The central character also doesn't resemble the in-game character portrait at all, which I realize was common in the 1990s, but I think it's an additional negative. The second one is clean and has a more sensible composition, and being drawn from a real photograph makes it more personal. The two images are very different in what they attempt to convey, though. If you really want to use the first one, maybe just use it as a guide for your own pixel art scene.
But personally, I would always recommend just avoiding AI-generated assets. If you're not skilled at art, work within your limitations. I am not an artist either, so my cover images are very simple and mostly composited from in-game assets and screenshots. It's not glamorous, but it works for me.
The goal of a cover image of course is to get people to click, but using AI for it is a gamble. You may get more views with a glossier (at first glance) cover image, but you will also turn off some people once they realize you're using AI assets. Whether that tradeoff is a net positive, I don't know.