Baby always constipated

So

Ok so. Hes 10 months breastfeeding no formula. Gets pureed baby food, only stuff like leafy greens or apples n pears, occasional avocado mixed with breastmilk. No carbs or constipating foods like bananas or sweet potatoes. He gets water too. These days he gets prunes pureed everyday too.

Yet he’s constantly constipated. Like hell go every other day n itll be a hard poop.

He gets plenty of exercise and we’re already doing everything we can diet wise without giving him juice which i dont want to do. Juice is what his ped recommended.

Whats our next step? More pureed prunes? Probiotics? Laxatives?

My first baby never had this problem. And this baby wasnt constipated when he started bbay foods.

Urg