How to Disable Prev and Next Post when it has no active link on it?

Hi there, I want to know how to disable active links or even everything when in fact has nothing there in previous and next post navigation..

See my “previous” and “next” in this blog

https://peacockdrawing.com/fahrelnissa-zeids-untitled-1950-inspired-digital-artwork/

I want to remove the prev button since it there is nothing on that button..thanks..

The page I need help with: [log in to see the link]