I was trying to find an alternative term for “users” twenty years ago, long before I heard the term “UX”. I concluded it was the closest I could find to an acceptable option. At least it acknowledges the relationship that the people in question have with the software: they’re using it. That may, as you say, eliminate context and reduce people to a single act, but at least the single act is a specific and relevant one. At the time, the alternatives I considered included “client” (implies dependency) and “customer” (implies a generically commercial transaction, implying that the specifics are irrelevant — this was at a time when the railways in Britain had notoriously dropped “passenger” in favour of “customer”.) My field isn’t design, I’m glad to say, but if you do manage to find an acceptable alternative to “user” in UX, I’ll be delighted to adopt it.
With apologies to Dominic Powell, terms like “Enjoyer”, “Interactor” and “Relator” sound too much like PR euphemisms and immediately make me wonder what kind of pup is someone trying to sell me. Honestly, I think “user” is still preferable to any of these.