I haven’t used a palette knife much, but I have watched a lot of Bob Ross in the past. Based on what I see in the mountains, less pressure with the knife will give you the effect of snow/shadows (getting your paint to break when applied from the knife). On your mountains, there are some parts that seem pulled out too much, so it might be from applying too much pressure.
If you don’t think that is the issue, a few other things could be it. First, it definitely helps to have a thicker oil paint. Second, when you pull out the paint on the palette, make sure that you do not pick up too much on the knife but rather, cut across and have a small roll of paint on the edge of the knife. Lastly, be sure to pull out the base mountain color (dark base) so that the next layer (your white highlights and shadows) do not mix with it.
I consider myself a beginner as well, but those are some things that came to mind, especially when I first started out. It’s a fun process of trial and error!