Would entering myself into A-Level maths be a waste of time? (Degree Apprentice)

I start a degree apprenticeship in Software Engineering in a few months... but the degree itself is not very theoretical. I have already been filling in the gaps in terms of self study of computer science theory (with the goal of it making me a more well informed programmer), and the apprenticeship is with a fantastic company working on exciting tech/projects.

I have been studying math in my free time, as i see it as something that will help me practice thinking logically and solving problems. I have been brushing up on my GCSE math as its been a few years, and i will now be working on a pre-calculus textbook.

I was split between working through a precalculus textbook (and then eventually calculus) or A-Level textbook, but I think there is some overlap. If I just self studied A-Level I would feel bad about studying it but not actually get the qualification if that makes sense?

But I feel like working as a Software Engineer just means that the A-Level Math would be a waste of time and money if I entered myself to do it offically. Since my work experience is what employers would be looking at after my degree apprenticeship