I have worked in IT for 15+ years, and I default to they/them for pretty much everybody. If I get a ticket in for an end user, and the name on the ticket is Jaime or something, it’s a coin toss on the gender, so I just go to they/them. Even if the name is more gender oriented, I don’t make any assumptions. And of course there is the case for foreign names I have never heard before. There’s no harm in using they/them. Or of course the ol’ “The end user”