Are you doing this from the inside or outside?
add curtain rod above window and wider than window.
We’ve done two ideas in our basement. You can see them here: https://www.frugalfamilytimes.com/search?q=Basement+window
You can also do amazing things with drapes by hanging them higher and wider than your actual window (but sill overlapping on the sides). :)
One thing you can try is to raise the curtain rod above the window trim onto the wall.
If you have a valance, raise it so the bottom of the material is just covering the top of the trim and not any of the glass.
Hang the curtain rod above window towards ceiling(taller) & past sides to widen. Here's videos https://www.youtube.com/results?search_query=how+to+make+windows+look+bigger+using+curtains