Laundry detergent?

Favorite non-toxic laundry detergent that is EFFECTIVE? Been using Mollys Suds (the powder version) for my toddlers clothes for the last year+ and while they smell clean, any smidge of dirt/mud/food seems to leave a stain/not fully come out. Many people rave about that detergent so I’m wondering if there’s something I’m doing wrong? Should I be pre-treating/soaking before every load? Is there another that you would recommend instead? TIA!