Any ideas? We thought maybe it's not getting enough light so moved it to the side of a window (not direct sunlight but brighter than the previous spot).

You're not getting many answers because this section is for edible figs. Your ficus lyrata doesn't fall into that category.

Confusing, I know. Especially since the ficus lyrata is nicknamed "fiddle leaf fig."

I grow a few ficus Benjamina, which has the same cultural needs as your plant.

A. Give it more light. A lot more. Right up in front of a south facing window is best.

B. Use a sharpened dowel stuck deep in the soil to tell if it's time to water. If it comes out dark, damp and stained with soil, do not water.

Check daily until it comes out clean and dry. Then water. Don't water on your schedule, water as the plant needs it.

C. Did you pot up or repot? Potting up means you'd take the plant out of the pot with roots and soil intact and place in a larger pot with fresh soil on the bottom and sides. That method isn't helpful if the plant is rootbound.

Repotting means you remove ALL soil from around the roots, untangle and prune roots and then place into a fresh soil.

What did you use for soil anyway?

your issues are likely from lack of light and overwatering.