Has your DD ever been assessed for ADD/ADHD, or has any teacher ever suggested dyscalculia or dyslexia or dyspraxia may be a problem for her?
There is a lot of forgetting and complete lack of focus going on, a lot of distraction, suggesting executive function or working memory issues.
If she has always (or even a lot in the past year or so) been a featherhead, had issues focusing, forgets homework, is inclined to blow off incidents like being late or not handing in homework and getting an F, or going without lunch, then she may need help/coaching and a different approach from simply the boot to the arse.
Someone who ignores or turns off an alarm and goes back to sleep on a weekday might have a problem with goal-setting and modifying behaviour in order to attain a specific goal, or might have a problem where difficulty in motivating herself has led to a sense of failure and a lot of anxiety about timekeeping and remembering things, creating a vicious cycle where every element feeds all the other elements. Can't remember/self motivate -> sense of failure, sense of dread > desire to shut her eyes and not deal with it -> being late -> sense of failure ---> avoidant behaviour.
She may not have the same potential for motivation, effort, or learning from mistakes that other 12 year olds have if she has ADD /ADHD, and may find it hard to rein in impulsivity or hyperactivity, or introduce a modicum of organisation into her life. She loses keys, disappears down musical rabbit holes, forgets her lunch, sleeps despite her alarm, forgets basic hygiene, it hasn't occurred to her to pack her bag the night before..... Efforts from others to push her in the right direction may only result in mutual frustration, and a continued sense of failure and anxiety on her part can lead to feelings of deep despondency and even depression.
Does she wash (shower or bath) willingly and regularly (daily)? Remember to use anti-perspirant daily?
Forgetting an important component of personal hygiene like tooth brushing is a little worrying. Many 12 year olds have by that age made it their life's mission to put their best foot forward when it comes to their appearance.
You could try to help her with her goal setting and ask her to come up with some solutions to the morning crisis points you have identified.
Ask her if she perceives it all to be a problem, and if she does, ask her what she thinks the problem specifically consists of.
Brainstorm solutions together:
Bag and lunch packed in the evening.
Spare Thermos kept at home.
Checklist on her phone that she needs to look at and share with you at end of school so she doesn't leave a Thermos in school.
Toothbrush kept downstairs - can do teeth in kitchen or downstairs loo.
I assume there is a DH there, and he has to be part of this too. You and he must both consistently put your shoulder to the work here. If no DH please ignore.
Has DD ever read any uplifting (for want of a better word) or positive or encouraging young teen manuals like 'The Care and Keeping of You', a title by American Girl publications, available online? It's very upbeat about hygiene and getting your act together wrt periods, supplies you will need, getting enough sleep, good nutrition, etc. Definitely suggests that someone aged 12 should be taking pride in moving from childhood to teenager, not trying to keep one foot in childhood and childish ways. Might be worth a try if not.
I highly recommend having DD take part in household chores, which she can do alongside you and DH (if present). There should be some sort of firm rota and you will need to be disciplined about getting her to participate, dishing out realistic praise and encouragement as she works. She should be able to do mundane chores with you - keep her room clean and tidy, empty or load the dishwasher, any pet care (supervise so pet won't suffer hunger, lack of water), checking for supplies like milk, bread, spaghetti, onions, other items that will go on the weekly shopping list, and should definitely be responsible for her own laundry for the entire cycle (clothes to basket, into washing machine/dryer/ onto clothes line/indoor rack, folding, ironing, putting away) with your supervision beginning at this age. She should be playing an integral part in the mundane household tasks.