When my boys were that age, they tended to fall asleep while they were eating. It's very common in newborns. It's hard to do this, but you have to try not to think about the ounces so much. Try to relax and just focus on following his cues. When you feed him, relax. Just hold the bottle and let him drink. When he has had enough, take the bottle away. If he doesn't fall asleep right away, rock him a bit or offer him a pacifier. Don't offer him the bottle again until he starts rooting or gives other signs of being hungry.
I was able to breastfeed my boys when they were newborns. This isn't a judgment at all, but when you breastfeed, you really have no idea how much they are eating. So you really are dependent on their signals. Try to stop noticing the ounces and focus on his signals. Some nights it felt like they were never going to fall asleep! But sometimes they just want to be held or rocked.
Finally, a 1 month old really is a newborn. He is still so new to the world. I know you are concerned about breaking a habit, but that's really not much of a concern at his age. He's going to go through so many changes in the next few months. Just as soon as you find one way to sooth him or get him to sleep, he's going to change and you're going to have to find new ways to sooth him. So right now you are used to feeding him after 30 minutes. If you didn't do that, I'm not sure he would notice too much.
Mostly he just needs you ... he needs you to hold him and rock him and help him feel secure. And even though it sucks, it's normal for him to have short periods of sleep and keep you up half the night. Just know that this, too, shall pass.