Most of the remaining ambiguity of three-letter acronyms could be avoided if people didn't get upset about redundant acronym expansion: "I cleaned with IPA alcohol after having an IPA ale."
[1] RAS syndrome: https://en.wikipedia.org/wiki/RAS_syndrome
ATM Machine grates on my sensibilities, since we all know what an ATM is and calling it a "machine" is both redundant and low-information. It's like calling an ATV an ATV vehicle (which I have never heard): would you call a truck a truck vehicle?
PIN number on the other hand, I'm fine with. A pin is a small piece of steel used in sewing, a PIN number is a number you type into an ATM.
I also find misuses of RAS syndrome fun. AAV vector isn't RAS syndrome. It stands for adeno associated virus vector. But people are eager to jump on whatever pedantry they think they can find, makes them feel smart I guess.
Some machines have 'machine' in their name, most don't. A milling machine, yes, but who says lathe machine?
ATM machine just sounds weird to me. The fact that the "M" stands for machine doesn't help but it's not decisive.
That's what I mean by redundant: it's like saying spoon utensil.