I don't doubt that the Empire and America had a lot to do with English dominance. However I do feel there is something inherently fun about English that is lacking in other languages I've encountered. Maybe it's just because it's my native language but I can't help but feel this sense of playfulness is picked up on by non native speakers as well. The article below is really interesting; it's by non English stand up comedians who have started performing in English. The general feel is that they prefer writing/performing in English and can have more fun with it than their native languages.
https://www.vulture.com/2020/01/stand-up-comedy-english-lang...
I'd say each language has pockets of playfulness that aren't found in others. Sometimes you find pockets that coincide to a surprising extent. It's like stacking layers of Swiss cheese.
For instance, Gad mentions in the article the expression "Got it" that doesn't have great equivalents in French. But French also has sentences that don't have great equivalents in English, or if they do have one it's not nearly as playful.
The one thing English has that most languages don't is a massive body of work and a dominant grip on international culture, and I think that's what the comics in the article are interpreting as higher overall playfulness.
English language is like Chinese: while simple structurally (no cases, constructive verb forms, etc) has a terribly complicated writing and pronunciation system, where there sort of are rules, but you never know when you hit an exception. Despite that, people take it up, because the important communication happens in English. (People who study areas like ML, or who work a lot with industrial production, likely pick up some Chinese, out of the same necessity.)