I’m not advocating Project Euler as the first thing someone should study.
I also disagree that the PE problems can’t be fun.
In the end, they’re a set of practice problems like any other. If they’re not enjoyable to you, don’t do a lot of them. But to say they’re not valuable is a bit dismissive.
I think I made a case in the article why PE is a good problem set, and most of my justifications don’t have to do with being left brained. They revolve around grokking a language, practicing clean coding, thinking about problem optimization, and generally getting more fluent in code.