That is correct. I treat my 15 Pro like having a set of prime lenses at varying lengths, and so only use 0.5x (13mm), 1x (24mm), 2x (48mm, which is 12MP out of the main camera’s 48MP), or 3x (77mm). In theory, anything between 1x and 2x should be non-digital zoom, but a crop of the 1x 48MP sensor. Anything between 0.5x and 1x, over 2x and less than 3x, or over 3x is digital zoom (crop + upscale). (For the 15 Pro Max, and I assume upcoming 16 Pro models, replace 3x with 5x)

As far as I know, Sony is the only company making phones with “actual” optical zoom, and not just a bunch of primes.