What kind of milk do you give your 1 year old

I started giving my baby whole milk once she turned 1 yr+ she started getting super constipated so I would give her the milk with tea so it wouldn’t be too tough on her and it worked here and there. My sister in law recommended to give her soy milk her daughter never got constipated I switched to soy milk I also talked to her pediatric and he told me milk is not something they need in they’re diet or self. But if you want to you can. So I did and I have seen it works a lot better. I’m just wondering doesn’t soy milk have a lot of sugar? 🤔 Any other recommendations?