I think different strategy for different kids. You just have to try to see what works more time, less time, more time with coveted screen time if moves fast, check lists with timer, phone apps.
I think the main goal is to stop yelling. I say just tell child you aren't going to yell or nag anymore and present them with the tools they need (clocks, watches, kitchen timers, check lists) and maybe practice on Saturday and Sunday...then explain that the child has the ability and tools needed and step back. Make a ziplock bag kit of travel tooth brush, pony tail holder, etc. items and say if you run out of time grab this and use it at school but you walk out the door at this time no matter what.
