“Expresso” version is not any worse than “Espresso” and maybe even better
A) Both are in the dictionary now: https://www.merriam-webster.com/dictionary/expresso
B) Both are understandable. No one would get confused by what you mean when you ask for one, pretty much anywhere in the world.
C) Some may argue that “Espresso” is truer to the Italian language. But that’s only if we go by pronunciation/spelling. The meaning… is lost. Espresso means roughly “expressed” or “pressed out” in Italian.
https://www.collinsdictionary.com/dictionary/italian-english/espresso
But… hey. Notice that one of the meanings is “expressed!” (in the sense of squeezed out). That’s exactly what “Expresso” evokes. So while “Espresso” preserves the Italian SPELLING, it loses the meaning, as the word “Espresso” means nothing to an English speaker, while “Expresso” evokes the meaning of “squeezing” or “pressing” the coffee through a filter.
This is more of a pick-what-you-want situation, and each has merit. There is no reason to prefer spelling and sacrifice meaning if want to stay "true" to Italian.
D) and sure “Expresso” makes it sound like something that is fast, and that’s false.
This just means we need to educate people on the meaning of “Expresso”: that it means “pressed through,” not “fast.”
But with “Espresso,” people don’t know what the heck it means either and still need to be educated…