My 9 week old usually has a long stretch of 3.5 hours, followed by stretches of 1 to 2.5 hours at night. Some nights are more like what you describe. I agree with @Becca - babies just vary! I recommend TakingCaraBabies (great free resources on her website and Insta; great paid course) for support with sleep!
Every baby is different . Some people have unicorn babies who sleep that long and are lucky. Some don't. Your baby will wake when he needs to feed. It's normal for baby to wake up to eat the first year some people just get lucky and have babies who sleep longer stretches. Mine is 9 weeks and wakes every 2 hours to eat at night 🙂 second baby
I don't think youre doing anything wrong, the longest my 8 week old has gone has been 4 hrs.. that only happened twice, usually he's up every 3 or more