This isn't going to be a tool recommendation but a learning path one. I recommend choosing a project to work on and then developing it using LLM assisted programming. The more niche and unique the problem, the less likely there's already a solution, and the more likely that the vast training data with a LLM will help you with that niche.

Ideally, you should try out all the tools. Each of them have advantages and disadvantages for each problem within a project. You might find that mixing and matching LLM apps gives you more expertise and skill over just sticking to your favorite.