8 month regression

How can I get my baby to drop to just 2 naps when he will only take 30 minute naps?

He’s always catnapped since he was born apart from the odd time he’s had longer, I just can’t seem to get him to always have longer naps. His wake windows are usually 2.5-3 hours until first nap, then 3 hours until the second nap and then sometimes he has a 3rd nap (not always) which is also 3 hours after the second nap and then bedtime is 3-3.5 hours after that. I’ve tried increasing his wake time and decreasing it to see if that might help him take longer naps but nothing seems to be helping. I’ve read he should be getting 14-14.5 hours sleep in a 24 hour period but he’s only getting between 12-13 which is usually 10-12 at night then 2 or 3 30 minute naps. He also wakes a lot during the night, mainly for his dummy/pacifier but then he seems to fight it from 3am and I usually have to give him a cuddle or bring him into my bed. I feel like I’ve tried everything I’ve read on the internet but nothing seems to be helping