Yooo, get it from me, you will have a burn out before your exams
Just aim for 4-8hours of study per day.
Maximum 4 hours on days when you have lessons and maximum 8-12hours in holidays or Weekends.
7-8 hours of sleep. And the rest chill as much as you can.
During your revision make sure to take breaks, I just do pomodoros.
Am an Alevel student currently predicted 3A*s, doing bio, chem and math, wouldn’t recommend what I do to anyone unless you doing heavy subjects as well.
On days I have no lessons, I will do 4-6hours of revision in the day and 4-6hours of revision in the night(I have access to a 24hour uni library)which sums up to 8-12hours a day, only on days when I have no lessons. And I sleep 6-10hours, that depends on if I get caught up watching a movie. On days I have lessons I still aim for 4-7