Just think of them like solar panels. Their leaves are trying to absorb the maximum amount of light as possible, and they can only do that by angling their leaves downward, to face towards the source of light. Many plants do this. If you're giving them artificial light, try keeping the light above your Ficus. In your first photo, the light off to the side is shining up at the leaves. This may be why all of the leaves are like this; they're trying to face down towards the light. Other than this, it looks perfectly healthy.

Ahhhhhh. Mystery of the sad fiddle leaf solved. I bought it in the winter and had a tall fluorescent light rugged vertically next to it. That's the light source you mentioned.Thank you!

A follow up question, if I now put a light source above it, will the leaves angle up? Or did that have to happen while they were growing? The Leafstems seem pretty firmly angled down...