Great work ! I liked the first version but seeing your edits I think you are on the right way.
Don't be too hard on yourself. I wouldn't call it a rip-off even if you are heavily inspired by someone else art. Gathering multiple references would, of course, be better and give you more ideas but aiming for an art style is nothing wrong. You are going to make it your own in the process anyway.
I am probably saying the obvious here but references are very important and help you overcome those moments where you get stuck. It doesn't have to be pixel art only, sometimes a photo or a painting can help you understand the shape and the texture better. Taking few minutes looking for those references can sometimes save you a lot of time afterward during the drawing process.
I don't know if there is much to analyze on my edit but my way of thinking was trying to see the big shapes at first. I think all artists are guilty of this, myself included, to zoom in early and get to work a small area for way too long when you should focus on the whole artwork instead. For your background I will recommend you to focus on the big picture at first. If it's an illustration, the composition, the values, the storytelling come first before worrying about details. If it's for a game, does your character stands out, the colors match, etc.
To sum up I think your rock is good and if it's part of a bigger drawing don't stress out too much on details.
Keep on the good work, I hope to see this background !
PS : Thank for the advice about attaching picture, I am fresh new on the forum and I didn't understand how those img brackets work
