Hii I received 3A* but I did bio chem maths but I also did around 6 hours of work from about 5 weeks before my alevels. But this was content I already kind of knew just revising it and doing past papers. I would do 2 hours of revision from 8am, then have a 2 hour break, then 2 hour revision then 2 hour break and then 2 hours revision. I then had free time from 6pm onwards. Rather than the amount of time you spend, the way you spend the time is more important. So if you are making notes it’s useless. You can find free condensed notes online. I would pretend I was teaching the content to someone else to understand the content and then I would do past papers and learn from my mistakes. I had a a book where I would write all the phrases and mistakes I made through past papers and organised them by topic. And I would go over my weaknesses the most. And then I think about 2 weeks before alevels I increased the work load and started doing about 8 hrs a day.
Working at the same time seems really tiring so if there’s anyway you can request leave just a couple of weeks before exams or maybe work after you’ve done all your work could be a way around?