I’d like to know if there is something I can do to close the gap or hide the gap in the blinds. Obviously, I can measure properly and purchase new ones but really trying to avoid that.
I’ve also thought about curtains, but it’s also something I’d like to avoid. Are there any solutions to this?
Here is another photo zoomed out. 
Measure the height, and buy a length of some narrow, white board at Lowe’s Depot. Stick it onto the glass with a small amount of double-sided tape.
I think some stores sell pre-painted trim boards. Or even solid white plastic ones.