I’d start at the beginning.
Bring back infant, junior, and middle schools.
Less focus on phonics and maths at infant schools - make it much more child-led up to age 7.
Formal classroom learning starting from year 3, focus on reading and writing once nearly all the children have the motor and cognitive skills to do so.
Middle schools from Y5, broad curriculum. Introduce lots of subjects, including MFL taught by specialist teachers. This is the perfect time for classes in finance, cookery, life skills, sex education, health and nutrition etc etc.
High school from Y9/10. Choose 8 subjects for a high school certificate. Get rid of numerical grades, just have pass, merit and distinction for each subject. At least one must be a numerate subject (not necessarily maths), at least one must be an essay subject (but not necessarily English), schools should have a wide enough offer to cater for a big range of choices.
A Levels for academic subjects, BTEC and T Levels for vocational subjects as before.
Get rid of ridiculous uniform rules, just have a school hoodie/ jumper/t shirt and that’s it.
Longer school day with time for extra curricular clubs and proper sit down lunch in the middle of the day.