All of the venues on the
https://entradasba.buenosaires.gob.ar/ site are, as the name suggests, government owned.
as mentioned above, dropping a digit was a workaround for the last decade or so to be able to use a us passport number in a form that was made for DNIs.
If you can print from either your phone, tablet, or computer, then you can download the tickets and print them. I generally print from my computer, so thats generally where I download tickets, but most people do everything on their phones, and if your printer has bluetooth, that should work fine for printing from a phone or tablet.
Me, I take my phone everywhere, in my pants pocket, and just keep the volume down while in events or spaces where it would be appropriate. I consult google maps, or look up nearby stores or restaurants, take photos, and, yes, post on social media all the time, and the phone is the device for that. I am pretty situationally aware, and in 15 years of wandering the streets of BA, never had anything stolen. But I dont look rich, just weird. Locals ask me for directions all the time...
also, Milei's "philosophy" has yet to trickle down to pretty much any governmental agency. The new head of ANSES was just announced last week. Some departments still dont have new administrators, and the ones that do are just starting to institute changes. The congress has not passed most of his proposed changes. He has managed to do a few things- he fired 7000 workers who only had 1 year temporary contracts, he has dropped price regulation on the colectivos, but as far as affecting change on websites or in the tens of thousands of government policies, his efforts have not yet been successful in most cases. The government is large, slow, and very difficult to change.