Here's my personal opinion about how you should approach this.
It's all well and good to want to cover undergraduate math courses. When you are actually enrolled in a university, you will have enough inertia and motivation to complete the courses.
However, when you are self-studying you are doing it all on your own. It's hard to be as thorough and cover everything.
And so I ask, what really is your goal here? You don't have to learn everything about mathematics, because that is in fact impossible.
My advice is to FIRST construct a bunch of projects, tasks or goals that require knowledge.
It could be something like
(a) implement a machine learning algorithm to do X from scratch
(b) implement a simple physics engine
(c) try to verify a number theory conjecture
(d) be able to solve all the exercises in a book
(e) be able to write up a compelling description/theorem/problem in math
(d) numerically solve the quantum mechanics equations of a certain system
Spend some time on material that will inspire you first to help get these goals. Numberphile on YouTube, or any of Brady Haran's videos, is a good place to start. But make the goals your own and make them personal.
Math is not a spectator's sport. Make sure to DO mathematics, not just LEARN mathematics.
It's all well and good to want to cover undergraduate math courses. When you are actually enrolled in a university, you will have enough inertia and motivation to complete the courses.
However, when you are self-studying you are doing it all on your own. It's hard to be as thorough and cover everything.
And so I ask, what really is your goal here? You don't have to learn everything about mathematics, because that is in fact impossible.
My advice is to FIRST construct a bunch of projects, tasks or goals that require knowledge.
It could be something like (a) implement a machine learning algorithm to do X from scratch (b) implement a simple physics engine (c) try to verify a number theory conjecture (d) be able to solve all the exercises in a book (e) be able to write up a compelling description/theorem/problem in math (d) numerically solve the quantum mechanics equations of a certain system
Spend some time on material that will inspire you first to help get these goals. Numberphile on YouTube, or any of Brady Haran's videos, is a good place to start. But make the goals your own and make them personal.
Math is not a spectator's sport. Make sure to DO mathematics, not just LEARN mathematics.