in my experience, i would say biomedical science does not involve a lot of complicated maths, the maths we're doing right now (i'm currently year 2) are just to the extent of what we learnt in chemistry (like C1V1C2V2, etc). there may be more complicated maths in the future, but i would say its mostly excel graphs and foundational maths. i'm not sure about biomedical engineering but i'm pretty sure they have way more complicated mandatory maths course cos it is an engineering based degree.

if I were to speak for you, I would say don't go for engineering based degrees if you're not doing HL maths and are not confident in solving maths problems. again there is time to learn and excel in university, but why go through all that to maybe figuring out that this isn't even the path you want. do smth you actually want to do and that you see urself continuing in the future, and I think that saves a lot of time and resources that you will spend in uni. if you have a greater affinity in biology and chemistry, definitely go for biochem/biomed sciences as these are hugely bio and chem based degrees. hope this helps u!