I’m aware of SN 6.9. You might want to check also the back story on AN 10.89, where Kokalika has bad thoughts on Two arahants Sariputta and Maha Moggallana. Tudu Brahma comeback to remind kokalika about them as good monks, arahants.Bhikkhu Ariyananda wrote: ↑Sun May 28, 2023 4:26 am SN 6.9 Turūbrahmasutta: With the Brahmā Tudu
[NOTE: To understand what is going on in this sutta, it is necessary to catch Kokālika’s misunderstanding of a non-returner. A non-returner is someone who is not reborn again in the human world. However gods who are non-returner can, if they like, make visits to the human world as is the case here.]
But NEVER a non returner announce a supreme or unsurpassed in future. In true dhamma, future hasn’t been set. Why the mind move to future, when the present experience can be seen/discern here and now.
That mean his mind is still moving and hasn’t let go the desire for future in sensual realm.
A non returner may comeback to human world to visit, but not to teach because they can’t. A non returner has given up sensual realm here and now. No more future for back to human womb. They may comeback to remind someone about true dhamma etc.MN 131 wrote:…
The Buddha said this:
“Don’t run back to the past,
don’t hope for the future.
What’s past is left behind;
the future has not arrived;
and experience in the present
are clearly seen in every case.
Knowing this, foster it—
unfaltering, unshakable.
Today’s the day to keenly work—
who knows, tomorrow may bring death!
For there is no bargain to be struck
with Death and his mighty hordes.
The peaceful sage explained it’s those
who keenly dwell like this,
tireless all night and day,
who truly have that one fine night.
…
Anyway good luck.