I do think it be better for a professional to be familiar with all existing paradigms of programming languages. But I don't think many, if any, would have been familiar with all languages. There is no reason for them to. For beginners, you can just start somewhere and then gradually expand your knowledge and experience. When you starts to get curious, you can watch some online courses or read some books/articles about different paradigms. And then you might get some better sense at this subject.