What do you girls use as an alternative to cow milk for toddlers?

My baby is almost 14 months. She’s been drinking cow milk since 12.5 months, but I nursed her a few times a day still up until last week. Suddenly her poop is concerning and the doctor suggested switching her to soy milk. A few people I’ve talked to are adamant that soy milk is not a good alternative. What do you all use if not using cow milk? I want to be sure my baby girl gets the best milk and all the nutrients she needs. Thanks for your input!