Vibrant Visuals uses “Screen Space Reflections” (or something of the like). This means that if something is blocked (such as the trees being blocked by the leaves), it is not rendered in the reflections. Here’s a link to a video demonstrating this issue: link
From the update’s notes: "Splitscreen is not supported with Vibrant Visuals and the game will switch to Fancy or Simple rendering if multiple players are joined locally."
A Graphics Processing Unit (GPU) would help, as just having a CPU (your a6 9500) makes it very difficult to achieve high performance.