The impossibility of "exactly once" is a theorem, not an opinion.

Knowing that, the article you linked is funny. It begins with maybe a thousand filler words complaining that all of this is "poorly understood", and it's not "impossible", just "very hard". Then it gets to the meat: Yeah well, you know, it's not quite "exactly once delivery", just "exactly once semantics", and to achieve that, messages need to be idempotent so that duplicates don't matter.

We all know that. It's called "at least once".