Hmm. My 7 (32gb) is even faster than my xs (64gb)I do remember reading something however about how higher GB phones had different NAND logic (for lack of a better term) and hence would(could?) bench mark faster. That would be splitting hairs though.
https://www.extremetech.com/mobile/...re-significantly-faster-than-the-32gb-version
But what you said is correct.