If the admission ever wonders about you academically, it won’t be about why you missed a few questions on math SSAT but about why you never attempted AMC or AIME (if that is true). SSAT is not considered to be a true measure of math talents; it tests if you can follow the curriculum. AMC and AIME are brain teasers - something those genuinely passionate about math would be attracted to.
If your perceived weakness is in EC, you would raise your chance by making academic not just academic but EC as well (ie a hook) but to do so you would have to get out of the ordinary domain such as grades and tests and go into research, publishing and contests. It would be interesting to see what PEA and PA would do with your case - ie someone who achieved the top of conventional means.
BTW, as you may well know, what determines the difficulty of a course is not the subject matter covered but the depth. A course in linear algebra can be taught in such a way to frustrate graduate students in math. PEA uses “problem-based learning” approach for its most advanced students, and I heard it challenges even the most advanced students. So highly unlikely you will run out of something to learn, I would assume.