y not said: “.. put another way,say he does attain the Sakadagami stage in that third Jati, will he still have to come back here until the human Bhava is exhausted before he ‘appears’ in a Deva realm?”
Bhava could be broken while in the middle of it.
– First is to realize that if one attains Arahanthood, no more birth in any realm when the current human physical body dies.
– If one attains the Sakadagami stage, the next birth would NOT be in the human realm, but in the deva realm.
– Even when one attains an anariya jhana, one’s next birth would be in a brahma realm. But of course, one would come back to the human realm in the future, and may even be reborn in the apayas.
– If a Sotapanna attains an Ariya jhana, he/she will be born in a brahma realm and WILL NOT come back to human realm or even deva realm.
So, there are various situations that one can analyze. It may take some time for all this to become clear. One needs to keep reading relevant posts (and keep contemplating, not just reading).