How to save set values of an instantiated prefab BEFORE runtime programmatically?

Hello.

I am trying to populate a two ints and a list of monobehaviour scripts for a pathfinding before runtime (from an Editor script) since I don't wanna calculate which nodes are connected in runtime (requires too much computing and will lag every time the scene loads).

 public class TileNode : MonoBehaviour, IPoint
 {
     public int xCoord = 0;
     public int yCoord = 0;
     public bool isWalkable = true;
     public List<TileNode> Connections = new List<TileNode>();
 ...

Here's the IPoint interface in case it matters:

 public interface IPoint
 {
     int X { get; }
     int Y { get; }
 }

Basically in short, what I want it so do this drag and drop:

except with code instead of manually drag&dropping everywhere.

EDIT/UPDATE: Okay so I managed to populate the X and Y and the List programmatically in Edit Mode (i.e. not runtime), but when I press PLAY, the ints X and Y keep their values, but the list's values disappear. How do I make sure my programmatically added List values don't get lost on the instantiated object upon pressing PLAY?

(I guess a possible(?) solution would be to programmatically create scriptableobjects that hold the necessary information, but I wanna avoid that if possible.)