How can I creatively transform a nursery and child’s bedroom in a small space with budget constraints and a dislike for the current carpet color?

Hey there! 😊
I hope it’s okay for me to share this here. I live in Perth, Western Australia.
Don’t mind the mess and the mismatched sheets, please.
I’m looking for some ideas (visual ideas are even more appreciated) on what to do with this children’s room. It’s going to be both a nursery and my 4-year-old’s bedroom.
We have a separate large playroom with a little library elsewhere. I might try to fit a small desk in the walk-in robe to create a quiet area for my eldest. Their clothes should fit in the bed’s storage drawers, while the baby’s clothes can go in the large change area’s storage.
We’re low on space, budget, and time since my second baby is due in a month or two. ❤️
All the furniture is currently white, and I’m thinking of getting a second-hand nursing chair. I may also replace the bassinet with a white cot. We can move everything around, although we really wanted to hang a wall-to-wall curtain until we realized the air conditioning unit is right in the corner. 😔 The two wall shelves can be removed, and we’re open to getting different tall storage shelves.
I haven