TL;DR

We first compare Waterfall project management to Agile. After that, you will have inputs which methodology you should use for your career planning. The post is based on a remarkable book written by Chad Fowler, The Passionate Programmer.

Waterfall project management is considered worse than Agile. But why is so?

The Waterfall is very rigid and is done is separated phases that flow in the strict waterfall direction. No back and forth, just one direction.

Why Waterfall usually fails? Because, in the end, you get correctly working software that nobody needs. Requirements from phase one changed or were wrong in the first place. The customer also does not know what he wants in the end. This constantly changes. Without that change, the Waterfall is entirely right for you. For example, if you are building a bicycle, you would have a rigid blueprints. Everybody knows what they need to develop, from the very first start.

Software is another kind of beast. It is invisible, and every programming language enables us to create something in an infinitive number of combinations. This is why Agile was invented.

You are doing Waterfall in small cycles, usually two weeks.

Which methodology you will follow in your career development plan? If, for example, you do Waterfall to become a QA manager in the long term, you could become a QA manager that hates the job.

If you strive to something with a high ratio of change, like context-driven tester or Cypress automation expert, you should adopt Agile. You would not use two-week sprints, but three-month sprints sound reasonable. At the end of the sprint, you could realize that context-driven is not for you, and you could try another school of software testing. Or you could recognize that along Cypress, you should learn another test automation framework.

The lesson is that your job satisfaction is equally important as the money that it brings.