I do the following:
I get up 15 minutes earlier than I think I need to
I supervise every single step of my kids getting ready and check in on them every couple of minutes (eldest has major adhd traits, and needs the prompting).
I get my 5 year old dressed myself (he is waiting for an ASD assessment, also has some traits of ADHD, and cannot dress himself in the morning yet)
We do everything in the same order every day- breakfast, get dressed, shoes, out of the house
The kids have school dinners most days, because I cannot also make packed lunches and get them out of time, it's too much
Everything we need in the morning is in the same place, under the stairs by the shoes and coats- school bags, winter hats, summer hats, wellies, thin coats, thick coats, gloves, spare bags, book bags, empty lunch bags, sunglasses. Its all there, even spare hair bobbles. In the summer I will put the suncream there too, so that I dont have to move from one spot to get everyone sorted.
Once a child is ready for school- dressed, shoes, coat, bag- I send them to the front door and they wait there, they are not allowed back into the main house. Once all 3 kids are there, I get my own shoes on, coat, keys and join them.
If they miss a timer- eg get up too late for breakfast- they miss that "thing" in favour of being out on time, they eat biscuits or fruit or a sandwich on the way to school on those days which are now rare thankfully. If I've not been organised enough to make sure there is school uniform, they wear whatever is clean (eg a plain tshirt instead of a school tshirt).
Most days my DH takes them once they are ready, but when he's away I have to, and on those days I have my breakfast and coffee etc once I get home after dropping them off. I cannot get myself AND the kids properly ready for school on time, so I do the bare minimum for myself and sort myself out afterwards.