How to redo matric and pass?

I’ve not done well at school. Was a very lazy kid. I’m now 22 and well yes, your teaches are right. When you’re sitting in your room weighing what little options you have, you wish you listened in class and studied instead of playing Xbox. That said. I want to add math, physics, biology to my matric subjects. The great thing is, mostly your matric marks matter. The not so great thing - I actually need the sum of years work to understand my exam paper, get a good mark and pass. The issue is, I’ve no clue about high school physics, biology or pure math. Never even had the subjects. The great part is - I’m getting enrolled into a program to help me learn those primary school basics before moving on to difficulties. The question I have - are those textbooks given by schools actually any good. I’ve saved up to buy them but if there’s any better resources out there, please let me know.