My Calathea needs help!

Hey everybody,

I bought a really lovely Calathea plant a few months ago and I got really attached to it. It's been having some issues though and I'm really worried and I don't know what I can do to fix it, I've been trying everything.

She's been getting lots of brown spots on her leaves, the edges get the same brown spots and it keeps getting worse.

I have a humidifier on quite a lot, I spray her leaves with water every day, I make sure the water I spray her with and water her with have been standing for 24h so it's on room temperature etc. She's getting enough sunlight, but not direct sunlight. I water her when the soil gets a bit dry.

I'll attach some photos, if anyone knows what to do to make it better please let me know!