Does anyone have any experience with their child not going poo?

My daughter is 4 years old and has always had trouble going poo since she was a baby we’ve talked to multiple drs and nothing they recommend has worked. She goes a week or more sometimes without pooing, we’ve tried restorlax, more water, She runs around a lot and we’ve tried rewards as well as encouragement but we just don’t know what to do anymore. If anyone has any suggestions or tips please help us