Outliers in Usability Testing and what to do with those findings?

I'm designing an edTech product and conducted a usability test with 5 students using interactive wireframes. One student, who had been identified during recruitment as having a learning disability, became frustrated very early on in the UT due to a multi-step onboarding experience that the student found tedious and repetitive.

I made recommendations based on just that one student's experience, but also knowing these improvements would likely improve the experience for all students (as the recommendation follows best practices and usability heuristics.) The team I work with suggested we do more studies before making changes based on one user's struggle.

What are your thoughts and experiences on basing changes on seeming outliers? Do more testing on the same exact wireframes? Or fix the problem and test again (my usual UX process for iterating.)

Part of the issue is that the team I'm working with is very sensitive to critiques and constructive criticism (or anything that recommends a revision to the work they contributed--which is incredibly valuable work!) So the solution might simply be in better communication between myself and them to explain my reasoning for changing something even if it is based on a single user.