Hey! I was in pretty much the exact same situation last year. I also got 100% on my take home assessment but 60-70% on everything else, which was quite a difference from my other subjects. Maths has never been my passion so I didn't really have the drive to try harder, do all the homework etc. and at the beginning of term 4 of year 11 I dropped to standard. It's honestly been so much better this year, I've gone from middle of my adv maths class to rank 1 across both standard 2 classes at my school! Dropping was a very tricky decision but I was also picking up ext 2 english and the workload would've been way too much.
I would say talk to a trusted maths teacher who knows your strengths – I went to my year 9/10 teacher and he said dropping to standard would probably benefit my atar, even though it's not weighted as well, because the work is just so much easier. It's really a big gap between standard and advanced, mainly stuff you would've already seen in year 9 and 10. Of course it's absolutely possible to still do really well in advanced with lots of hard work (and those marks aren't at all bad!), but for me personally dropping to standard alleviated so much stress and I'm really glad I did it. I would stick out your prelims first though and see where you're at because otherwise you'd have to do even more revision. Hope this helps and good luck! 🙂
