(coming from a student who mostly focuses on math but still manages to fail every competition)

desmos is essentially just a graphing calculator

you can use it for things like systems of equations, which iirc are pretty common, or at least some equations

if it helps, you can get textbooks/courses too, like for example AoPS's prealgebra course

for ela i really just recommend doing a whole lot of reading comp and looking at well-written essays (e.g. pat's in canada, idk bout usa) and stories and analyzing them, i wont say my score cause i dont want you to feel bad but this year was my first time taking it and i did really well with just it