What’s wrong with my boyfriend’s monstera? Please help me bring her back to life!

As you can see, she’s pretty worse for wear. I plan to change that but have no clue what she needs (other than a support, which I plan to do)

Some background: She was in a shady spot for some time, we’ve now moved to somewhere with more light but my boyfriend had her pressed up flat against a window that gets lots of sun, so i’ve now moved her so she doesn’t fry.

Watering was sporadic and I suspect my boyfriend may have overwatered her at some point, but i’m not 100% sure.

Any help and advice would be greatly appreciated!!