I have a feeling that in FAANG and other more or less big companies the stack of CS questions for mobile devs is different from the questions for regular SE roles (like less complicated data structures) and there is a bigger accent on the platform specific knowledges. Is my feeling true?
It's true for Uber.
Just study leetcode and ask to be put in a generalist loop unless you are extremely knowledgeable in mobile and would be comfortable with an interview. If you get an offer, try and match to a mobile team