How to create nested map from firestore data in flutter

Question

I have this api i need to send data to that has a payload object that looks like

"members": [
 {
 "names": "ben",
 "date-of-birth": "1978-01-01",
 "gender": "Male",
 "surname": "surname",
 "role": "Partner",
 "total-cut": "100.00"
 }
 ],

basically I can put in a couple number of members in there like

"members": [
     {
     "names": "ben",
     "date-of-birth": "1978-01-01",
     "gender": "Male",
     "surname": "surname",
     "role": "Partner",
     "total-cut": "100.00"
     },
     {
     "names": "bennyy",
     "date-of-birth": "1978-01-01",
     "gender": "Male",
     "surname": "surname",
     "role": "Partner",
     "total-cut": "80.00"
     },
     {
     "names": "ben",
     "date-of-birth": "1978-01-01",
     "gender": "Male",
     "surname": "surname",
     "role": "Partner",
     "total-cut": "100.00"
     }
     ],

I have this data inside firestore in a collection as different documents. How can i iterate the response from firestore into this format. Currently what I am getting is a key-value format which this api does not follow clearly from the above sample this is my code, I create an empty map

final Map<String, dynamic> memberDetails = {};

then get the data from firestore and for each document i add it to the map I have created above

How can i solve this to get the format that i have up top