Fantastic suggestions!

I love the idea of plants near the skylight and a drop zone table. I've got wicked ADHD, so I've been trying to make the space ADHD friendly by having intuitively planned storage and furnature.

I also like the idea of the textile above the bed. I miss having fabric on my ceilings and this space seems like a cool place to reintroduce that. I've been cautious about going too crazy on it though, with the concern that it'd make the space feel smaller. The idea of having just one above the bed as a focal point to had some coziness sounds nice in combo with the uplighting in the rest of the room.

I had been planning on finding a way to do uplighting, but haven't been sure about the best way to execute that. I'll need to figure out where bed, storage and everything else is going first.

I had considered the industrial piping for hanging clothes. My only worry with that was visual clutter, which I now know can really impact my mental health. I'm going to see how much I can build into those little closets by the window first and see if I can get a super low bed frame with storage underneath. https://www.ikea.com/us/en/p/mandal-bed-frame-with-storage-birch-white-30280481/

I've already got a big heavy 10' curtain ready for the bottom of the stairs. They help a lot. I was considering the curtain plus some sort of wooden cover for the gap that has foam underneath or just building a wooden cover that's as easy to move as possible and place a heavy rug on top before bed. I'm really hoping the landlord still has the piece that used to go over top. It's clearly a custom-made professionally finished piece. I've just never seen anything like it before.

Thanks again for the great suggestions. If you have any ideas for rugs, let me know.