y not said:
“He does not say that he transmigrated in those 14 as a Sotapanna. He was NOT a Sotapanna back then.”
Even though I do not know if this was clarified in the sutta, I think this is the case as well.
King Bimbisara became a Sotapanna about 2600 years ago. The lifespan of even the lowest deva loka is supposed to be 9 million years. If he exhausted 7 deva existences in addition to 7 more human jathi after becoming a Sotapanna, all this would not be possible in the 2600 years that have since passed.
And even if the exact calculation of the lowest deva loka lifespan is not confirmed, then it should be at least thousands of years, and even then the above would not be possible.