My gal also 2.5 months old n can stretch up to 6 hours between feedings at night. Didnt train, she just didnt wake up n we let it be. But we do swaddle her for night sleep n I read swaddling reduces arousal. So it could be why she’s not feeling her hunger so much.
I start night time routine for her about 9pm with body wipe down, change into pjs, baby lullabies or sing to her. Also made sure she has 1 last feed before she sleeps so she won’t go hungry. If this last feed is sometime ago and it’s still not time for next feed before she falls asleep, I will latch her for a while.