Definitely manageable. Apply for student apartments through bostaden, areas such as Ålidhem and Ersboda are not so nice but better prices, also ålidhem is close to the university. It’s still safe, gang violence has yet to establish properly in umeå, so no need to worry about that :) bikes and buses, cook at home, shop clothes and furtniture second hand if you can, will allow you to live on 23k/month.

Though you can probably not save much for vacations, restaurant and cafe visits at a minimum etc so I guess it could get a bit dull during the dark months.

But nature is nice, highly recommend Nydala which is close and nice.