My custom function for Updating a data string in an array causes deletion of all other data

I have a "gamedata" string array that on the game start is filled with all data currently stored on a text file, which completely works. I have this script that would update, or add if there wasn't any, a section of data (inputted as a string[] ) into the game array. What seems to be happening is that only ONE of the data that I have using this script is being used (I believe it's deleting the other data because whenever I manually input the other data it just removes it). I do use some custom scripts / commands in the command script

Goal of the script -> Take an array with a specific name, and update the existing data into the gamedata array, or add it if there is none already, starting with a bunch of dashes with the name and ending with the save bunch of dashes

Command.ArrayAddString(string[] arraystring, string objecttoad); // This works fine, I have proven it to work multiple times. All it does is add an item to an array

endmark is just a bunch of dashes "------------" as well as the startmark

 public static void UpdateGameData(string[] Data, string DataName) {
         debugupdatestuff += 1;
         string StartName = StartMark + DataName;
         string[] Return = new string[0];
         
         bool FoundStart = false;
         bool FoundLast = false;
         int Start = 0;
         int End = 0;
         int Selection = 0;
         // Find the start and end of the data if the data is already in the string array
         foreach (string item in GameData) {
             if (FoundStart == false && item == StartName) {
                 FoundStart = true;
                 Start = Selection;
             }
             if (FoundStart == true && FoundLast == false && item == EndMark) {
                 FoundLast = true;
                 End = Selection;
             }
             Selection += 1;
         }
         Selection = 0;
         // find all the data *not* in the range between the start and end and put it into an array
         string[] ExtractedData = new string[0];
         if (FoundLast == true) {
             
             foreach (string item in GameData) {
                 if (Selection < Start) {
                     ExtractedData = Command.ArrayAddString(ExtractedData, item);
                     DebugLogging.Log(debugupdatestuff.ToString() + " added item" + item);
                 }
                 if (Selection > End) {
                     ExtractedData = Command.ArrayAddString(ExtractedData, item);
                     DebugLogging.Log(debugupdatestuff.ToString() + " added item" + item);
                 }
                 Selection += 1;   
             }
             
         }
         // Set the gamedata to all the places above, in essence removing the data input that we want to update
         GameData = ExtractedData;
         // Adding the data we want to update (updated data) to the end
         GameData = Command.ArrayAddString(GameData, StartName);
         foreach (string item in Data) {
             GameData = Command.ArrayAddString(GameData, item);
         }
         GameData = Command.ArrayAddString(GameData, EndMark);
        
     }

Here is what the data SHOULD come out with

 ----------Player Location
 2.061744
 11.5
 6.801244
 ----------
 ----------Player Health
 500
 ----------

And here's what its actually coming out to

 ----------Player Health
 500
 ----------

Note that the player location is executed BEFORE the player health

I do know that all my other scripts are in working condition so I'm almost confident that this is what's not working

I also don't want to really go into the list format because if I did, it would need to be converted back to a string array before this script ends... I don't know anything about lists or other too too *complex things (although I am able to learn with enough effort)