percysmith suggestion is very smart.
Your idea of booking an award the first day it is open (roughly a year before departure) makes the whole concept of building a MCA very expensive with so many segments. Because the last segment is the one helping you to qualify for MCA, I doubt that your strategy will work anyay.
Anyway, the schedules for 2023 are very hypothetical at this point.. Why don't you wait until February 2022 and try to book then the whole itin.
I wish you good luck as airlines are not releasing many awards currently.