The differences between Spanish "dialects" are overstated IMO and closer to accents. No two Spanish accents are as different as the dialects of Arabic or dialects of Chinese are from each other. People will share anecdotes about not being able to understand different words(like straw, car, computer) but the underlying grammar is the same in all varieties. Im natively fluent in both English(US) and Spanish and I find English accents way harder to understand than Spanish ones. The only time Ive felt completely clueless listening to English was talking to a Scottish man.