optical zoom

I've been researching this extensively but haven't found a definitive answer. I own an iPhone 15 Pro and I'm interested in understanding which focal lengths utilize optical zoom rather than digital zoom. Additionally, I'm curious about the camera capabilities of the iPhone 15 Pro Max in this regard.

I noticed from youtube that the pro max camera has options of .5x 1x 2x and 5x optical zoom. Does it mean there is no other options between 2x and 5x optical zoom? It looks like some people are guessing that any zoom between 2 and 5x in pro max would be digital zoom. I'm so confused about this.