I’ve also had similar problems! I honestly struggled a lot with these bottles as tear 2 is WAY too slow and teat 3 my little one was gulping and it was too fast. This meant that feeds were taking too long on teat 2 and he was falling asleep and never finishing the bottle which then lead to snack feeding! I’ve now changed to MAM bottles (teat 1) and they are much better! He finishes the bottle and is always satisfied. I’d honestly consider changing bottles.
My daughter is 9 days old and using the Avent Anti-Colic bottles and is using a Size 2 teat fine but I’m looking to change to 3 soon. Hope this helps!
My first baby used the 1nipple just fine and progressed through to 2 and 3 and is now on 5s. My second baby (2 weeks old) could not get anything from the 1s. I skipped straight to 3s and he's doing okay but I'm thinking about going to 4 already.