Baby getting up to feed again after ~30mins

Usually I combo feed - morning boobs, pumping with supplemented formula in the evening since I don't produce too much, then top up with boob if he's still hungry. Today I breastfeed all day and he's just waking up after the shortest amount of time, always ready to feed again. Is this a bad sign?

I was considering just breastfeeding him throughout the day like this and just bottle at night, but now I feel like maybe he's not efficiently transferring milk. He has a good latch, but breastfeeds only 5-10min per boob before falling asleep / becomes very occasional suckling.

Is this normal? He's 3 weeks.