Figma's letter spacing can't be directly used in Android as the values don't match. They need be calculated by:
Figma letter spacing / text size
So if the letter spacing in Figma is 0.15 and text size is 16px, the resulting letter spacing would be 0.15 / 16.
More information in this thread https://stackoverflow.com/questions/39100969/how-to-calculate-letterspacing-for-textview-from-sketch-values