I have such a question, my son doesn't poop for 5-6 days, he only poop…

I have such a question, my son doesn't poop for 5-6 days, he only poops when I give him microlax a little bit because of that, not the whole tube. He poops clean on the GV. Poops with mood, the belly soft, why is it like this? Could it be that I don't drink soups as often now? Something bothers me that it already happened three times like this, when two times I gave him microlax, then he pooped 2 times a day for 4-5 days, then again it started. I do massage and put it on his belly. But if he wanted, I think he would at least try to move.