Learning Blender: tuto by tuto or full training?

I'm already using Blender to make product renders, not too advanced at this stage. So far, I'm progressing by doing specific research each time I want to do something, I usually find a dedicated tutorial. For example if I want to do a Line Art render: https://www.youtube.com/watch?v=HYs3mOV8mmo.

To progress, I noticed that there are quite a few complete training courses, on Udemy for example or other e-learning platforms. A structured training could allow me to go further and have a global knowledge of the software. But it still requires an investment in time and money.

Do you think it's worth it, knowing that I'm only interested in the rendering part of Blender? Or do you think it's better to learn the things I'm interested in, with tutorials?

The answer is probably going to be "it depends" but I'd like your opinion or maybe some feedback on this.