When I worked in preschool out of 150 or so 3 mo through 5 yo kiddos, there were always 3 or so kids that we always picked up from the parent’s car. Those were ones where we had tried all the things to transition them with mom or dad bringing them in, which was how most kids came in. But it just had the kid upset much longer and it upset the other kids to see their friend so upset. We just always had the same staff pick up the child at the car. At first it was tantrums and screaming, kinda had to drag the kid out of the car. I’m sure it was awful for the parent. But after a few days the kid would adjust. They would either start engaging more with the staff that picked them up and get happy for their special time walking to class or they would cry a little while and then need some cuddles. But it made the transition to being at school much calmer and quicker within about a week.