If your goal is literally to get good at math through Calculus, Differential Equations and Linear Algebra... I feel like the best approach is working through good books (reading, taking notes, and doing problems out of the book then checking answers/solutions) and hitting Youtube and Khan Academy for help with certain topics.

Fortunately, there are a lot of great older-edition, cheap used books on Pre-Algebra, Geometry, College Algebra, Pre-Calc, Calculus, DiffEq and Linear Algebra, etc.

It will take some time to master all the math you want... but if you structure your studying so that are you actual enjoy studying (i.e. enjoy the process), you will 100% get there.

I'd be happy to list out of some book recommendations.

I will echo the sentiment of others that you don't need to be a math expert to use machine learning libraries effectively in many cases. The problem is, without the math expertise you won't always be able to identify the cases when you are using the wrong approach, etc. And you'll have a harder time applying cutting edge ML to new problems.