Yes, believe it or not, you understand the core of the issue! That ambiguity was the problem. I'd be in a cafe where the menu said "coffee" and I'd order it with no way of knowing what I was actually going to get until it was in front of me.

More often than not in my anecdata, it was a bad Americano. And not a good Americano. A bad one.

I rarely see people order Americanos in Europe, and when they do, they are usually Americans (and actually, the invention and name of the Americano is indeed to please American soldiers who were not used to espresso). Most cafes won't really know what a good Americano is supposed to be because it's unusual to order one and the baristas themselves probably never drink it. A typical customer either wants a tiny cup of pure espresso, or a milk-based drink like a cappuccino.

In at least some modern (European) places it's called batch brew. If they don't have that either, your next best option will be a v60.