At what age did your baby start sleeping longer stretches at night?

Ka

I have a 9 and a half week old who still only sleeps 4 hours in one long stretch, followed by 2 hours then 1 hour. Wondering when he will start sleeping 6+ hours in a row? We're following the eat, play, sleep routine during the day so I'm hoping it will help. He still eats every 2 hours, plays and then naps 30 mins fairly consistently. 🤷‍♀️ There was ONE night he slept 6 hours in a row last week and I got soo excited. Never happened since unfortunately!