Chinese has the most native speakers. Spanish has the most countries and English is the most common second language. So between the three of them you have a huge chunk of the world population covered.
Not saying there really should be an “official” language but there will need to be a lingua franca because putting two dozen languages on a street sign doesn’t help anyone.
2000 characters gives you a ton of coverage unless you’re working with obscure topics (which you’ll pick up from context anyway). I would also say that speaking is significantly more important that reading, writing, or listening, and if you focus on that as a first objective (but not the only objective of course), everything else will come pretty naturally.
there would not be an official language in such a scenario
We will learn to communicate using computer programming language? or (computer) binaries? Maybe talk to each other through an open AI device that translates it into the hearer’s first language?
spoiler
Uhhhh, this link not intended for use by persons with fully functional hearing.
Pretty obvious that it should be Wakandan.