Help! Baby Constipated Question!

My son is 14 months old and has issues pooping, he eats all kinds of food and was breastfed up until a week ago. He would go a week without pooping at times- I’ve tried the prune juice, apple juice, pear juice, warm bath, massaging belly, bicycle legs and NOTHING helps. I’ve had to resort to the “Windi” gasspasser and also baby suppositories. I mentioned this to his Dr and our Dr recommended that we give him half lid of miralax once per day- I started it and it works and keeps him more regular- now he will go every 2-3 days instead of a week but I don’t like the idea of giving him one thing for this everyday if there is a better natural approach that I am not aware of. If anyone has any recommendations please let me know.

Not sure if genetics play a role- I am also one who doesn’t go every day- I go every 2-3 days as well- his dad however is very regular.