I would suggest keeping her Hb above 9 with transfusions to assure proper growth. If you have a doctor who is familiar with using hydroxyurea, I would suggest giving it a try, along with folate and wheatgrass.
I would not wait for the new med to be approved. Phase 2 trials showed it works better than hydroxyurea. Luspatercept can be tried once available, but for a growing child, growth and development must be the first concern, so regular transfusion should be considered for now.