Hello Francis,
I think there may be a misunderstanding.
With a normal reboot, setting noout is usually not required. When the OSDs on a node stop, they are first marked as down. They are only marked as out after the mon_osd_down_out_interval expires (600 seconds by default).
Therefore, during a normal reboot, the OSDs should come back before they are marked as out, making noout unnecessary in most environments.
Are the OSDs actually being marked as out during your maintenance reboots? If so, how long does the reboot take, and what is your configured mon_osd_down_out_interval?
Understanding why the OSDs become out would help determine whether automating noout is the right solution or whether there is an underlying issue to investigate.