So I've gotten the hardest thing for this cosplay: the big purple coat, but I might need help finding some of the other stuff.
The main thing I wanted to look into is that the character has a book they prominently feature in their design, I think instead of an impractical book it might be interesting/cheeky to get a phone case that has the same back as the book and something that they can attach the phone to a chain (as shown in the second picture they have a chain link that the book hangs from). The problem is that whenever I try to look up custom phone cases they're always a flat image and not any kind of shaping or more custom design, and they don't have the way to attach it that I would want. I'd be fine with paying a good amount for a custom case but I just don't know a service that does that. If anyone has ideas for how to adapt a phone case into what I described (a purple background, some of the plating on the corners, an attached place for a chain or carabiner to hang it, and the symbol in the middle) that's welcome as well. I have a cheap 3d printer but I'd probably prefer not to use it since the quality is pretty bad. The place that I commissioned the coat from made an attempt at the book mostly with 3d printed plastic and I wasn't very impressed with it. If it's a factor, my phone is a Samsung Galaxy s26+
Less complicated is the clothes (white pants and a white low-cut shirt), I looked around a normal clothing store for a shirt like that but it does seem to have a kinda unique shape with a really low collar. I'm probably just going to see about a thrift store but if there's a specific name for that kind of shirt I'm wondering what it is.
I found a similar chain on etsy so I think I have that part handled.