If you're a bit of a shut-in like I am and don't like natural light, easiest solution would be a roll of aluminum foil (heavy gauge preferred) and duct tape. If you seal it right, it will be as if it were a solid wall there. Then you can easily hide the look of the ugly aluminum foil with the blinds you have.

Amazon has this blind that looks removable although it's a bit of a pain to install and take down: https://www.amazon.com/Easynight-Portable-Travel-Blackout-Blind/dp/B017AFTPH6?

Finally, you could just find a way to take that blind down and replace it with something you'd find in a hardware store, but that could be rather expensive given other options.