In Spanish KnY is "Guardianes de la Noche" (Guardians of the Night) and I've never heard a single person say that it was good. Most people I know just call it Kimetsu.

I also personally use SnK, AoT means "ahead of time" for me. For so long I was confused when people expected me to know AoT as Attack on Titan.

That said it really depends on the title. Some titles suck in other languages, some don't. I mostly pick which to use on length, how stupid the translation sounds, and if the translation is confusing for me.