UML – Where do I start? Do I even need to learn it?

I'm currently learning to be a developer. When it comes to problem solving, I find myself struggle a lot to understand the problem, it's requirements, how things connect with each other, etc…

Then I stumbled across Mosh Hamedani's design pattern course and found out about UML – The Unified Modelling language, and think to myself "I need this! This will help me become a better problem solver / developer."

I really hate the feeling of not knowing what the hell I'm doing. Even a simple example like making a counter app in React. Just keep watching tutorials over and over feels pointless when I lack the fundamental understanding for software development.

So with this post, I want to ask: Will UML help me:

1. Identify / Organize the requirements when building software?
2. Better Visualization / Understanding Algorithms & Data Structures?

With UML, can I:

1. Make diagrams to explain & understand how Algorithms work? (Recursive functions for example).
2. Make me knowing the entire structure of what I'm going to build, from simple to big complex systems?

If UML can do all of those, aside from Video Tutorials from Youtube, where can I find free resources to learn & master UML?

Thank you!