Account recovery

I think I could of located a great answer to why some folks can’t add a family member or a close friend using an iPhone phone with IOS or later. I have added both of my grown daughters as my account recovery people. My oldest daughter it always states, “unavailable”. Their iPhones are newer then mine. I have an XR they both have 13 Pro Max. It state… that the person you add must be using 2 factor and a passcode (I’m guessing a passcode would also include Face ID) at least I hope. Waiting until my daughter wakes up for work for her to reply to my text. (I thought I could add a pic, where I circled both of those items)