Post data to Server PostgreSQL using Flutter

What is the best practice to post data to a server, currently my database is a PostgreSql.

I would be posting to a REST Api and I want to be safe, to post I was going to use a token to verify that they are from the app but then if someone decompiles the app they will see the verification token and could then post to the API

String token = esR3bJM9bPLJoLgTesR3bJM9bPLJoLgT;
String apiUserLikes =  current_server_address + "/api/user-likes/?token=$token";


final response = await http.post(
Uri.parse(apiUserLikes?token=$token),
headers: <String, String>{
  'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(<String, String>{
  'userID': '1234567969855478',
  'UserDisplayName': 'John Jones',
  'liked': 'true',
  'dateLiked': '2022/12/05 00:00:00',
  'eventLiked': 'Music concert at The stadium',   
}),
);

What is the best way to protect users details and still post to the server

Thanks