cursor in mail on iphone 13

hallo, i'm a newby iphone user (but longtime macbook user). i'm trying to write a mail on my brand new iphone 13 mini but cannot edit typos because there seems to be no way to move my cursor. i've tried the 'magnifying' haptic press' (drag cursor and drop it where you want it) but it jumps back instantly. so i tried the 'press hold space bar and use keyboard as track pad' variant ... cursor still jumps back immediately to the beginning of the line. this is super frustrating as i've just spent half an hour watching people on video perform this function perfectly. what am i doing wrong?