Pay phones still existed in 2019. You might find them more in big cities with lots of public places & small towns. That computer was one of those public use library computers that i'm sure are still found in some libraries. the timeline is definitely different than ours, but there is still regular mobile devices & technology. Some tv shows incorporate certain things to help set the mood or vibe of the show. A series of unfortunate events has culture & objects from all sorts of time periods. Fans still don't even know what time period ASOUE takes place.

The Umbrella Academy takes place in another dimension

Idk actually. Maybe they did or is it just the library was cheap?

Yeah, the thing with the cars always confused me. None of them seemed to have iPhones or whatever, and not the modern cars that we have now, but the theory that it takes place within different time periods makes sense

I remember Luther (if I'm not mistaken) was shown to use n IPhone in s1. Probably 7,8.