TLDR: past papers are for me the best method of revision, do them in timed condition for your respective subjects and mark them harshly using mark schemes, examiners reports etc. scrutinise your exam technique and focus on maximising your potential marks by evaluating gaps in your knowledge and understanding, as these are clearly exposed by your past papers results. your detailed notes may be helpful here in filling in gaps. 25 topics may sound like a lot but split them up and prioritise by ordering them in difficulty, length etc.
your gcses sound great, your're clearly an academically capable student. dont underestimate yourself. you have plenty of time left, but it may be time to consider different revision strategies than the usual note taking. effective revision is different for everyone, but your current method isnt getting you results and most importantly is not motivating. please dont be scared to ask your teachers for help, end of the day they are getting paid and have a responsibility to help you, not sit there and humiliate you. if you dont want to ask your teachers then consider others in the department that dont necessarily teach you.
procrastination is a big issue, but it helps when you have a clear goal in mind and therefore motivation. as-levels are not the end of the world, but you should aim to do well as they can determine a big part of your UCAS predicted grades. these same grades may be used to apply to uni; think about what you want from your a-levels by the end of all this and what they can do for you in the long-term. you will thank yourself down the line.
dont burnout from overworking, one of the biggest mistakes a student can make. take time off whenever you feel necessary, do something you find enjoyable and dont feel like you have to give up on hobbies just because of looming exams. an effective work-life balance is subjective, so dont base your individual needs on other peoples typical days.
best of luck.