Its not good to be overly detached or clingy in a relationship. You can tell her about how you feel and come up with a compromise.

Emphasize on how you worry about the "few hours every day drawing", "eyes glued to the computer" and "draws in the middle of the night". It sounds detrimental to her health and it shows you actually care. if she comes up with an excuse like " I have an "idea" and had to draw it " then give her a mini notepad to write down or sketch the idea :D

how she spends her own money is her choice. ( though, I think she shouldn't waste it as she already has one) Just make sure she isn't spending your money on stuff she doesn't NEED << applies to after marriage if you are willing to deal with her spending.

Referring to "put your toys away and grow up", if she's in a major related to arts, you have to deal with this issue because its actually good for her to gain publicity haha. If not, you can talk her into focusing on things related to her actual major and pathway.

If she insist on drawing, you could check in on her and make sure she is keeping up with her studies and taking regular meals. optional: you can even learn to draw with her just to spend time with her.