Assistance Request: Dynamic Tilemapping

Search Engines have failed me in looking for the answers I need. My issue is a CS0122 Inaccessible due to protection. the objective is to have 1 line place all of the tiles on a tilemap based on data from a list.

 using System;
 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Tilemaps;
 
 public class Game_Supplies : MonoBehaviour {
 
     //Serialization Inputs
     public Map_Data _MapData;
     public Tile_Sets _TileSets;
     public Object_Sets _ObjectSets;
     public Monster_Sets _MonsterSets;
     public NPC_Sets _NPCSets;
     
     //Tile List Sets
     public List<AreaData> AD = new List<AreaData>();
     public List<TileData> TD = new List<TileData>();
     
     //Tile Placement Sets
     public int _TCount;
     public int _TPlaced;
     public Vector3Int _Position;
     
     void Start(){
         GenBaseMap();
         TD.Add(new TileData(new Vector3Int(0, 0, 0), "_Ground", "_GroundField"));
     } 
     
     void GenBaseMap(){
         _TCount = TD.Count;
         for(_TPlaced = 0; _TPlaced < _TCount - 1; _TPlaced++){
             Vector3Int _TilePos = new Vector3Int(TD[_TPlaced].Data_TilePos.x, TD[_TPlaced].Data_TilePos.y, 0);
             string _LayerName = TD[_TPlaced].Data_TileLayer;
             string _TileType = TD[_TPlaced].Data_TileType;
             
             //needs modification for variance
             //_TileSets._TileLayer._Ground.SetTile(_TilePos, _TileSets._RuleTiles._Ground_Field);
             _TileSets._TileLayer(_LayerName).SetTile(_TilePos, _TileSets._RuleTiles._Ground_Field); //Error is in this line "TileLayer(_LayerName)".
             
             _TPlaced++;
         }
     }
     
     public class TileData {
         public Vector3Int Data_TilePos;// Store the location of the area center
         public string Data_TileType;     // tile type from "Rule_Tiles"
         public string Data_TileLayer;    // tile layer from "Tile_Layers"
         public TileData (Vector3Int _TPos, string _TType, string _TLayer) {
             Data_TilePos    = _TPos;
             Data_TileType    = _TType;
             Data_TileLayer    = _TLayer;
         }
     }
 
     [Serializable]
     public class Tile_Sets {
         public Rule_Tiles _RuleTiles;
         public Tile_Layer _TileLayer;
     }
     
     [Serializable]
     public class Rule_Tiles {
         public RuleTile _Ground_Field;
         public RuleTile _Ground_Forest;
         public RuleTile _Ground_Town_1;
         public RuleTile _Ground_Town_2;
         public RuleTile _Ground_Town_3;
         public RuleTile _Ground_Dun_1;
         public RuleTile _Ground_Dun_2;
         public RuleTile _Ground_Dun_3;
         public RuleTile _Ground_Boss;
         [Space(5)]
         public RuleTile _Wall_Field;
         public RuleTile _Wall_Forest;
         public RuleTile _Wall_Town_1;
         public RuleTile _Wall_Town_2;
         public RuleTile _Wall_Town_3;
         public RuleTile _Wall_Dun_1;
         public RuleTile _Wall_Dun_2;
         public RuleTile _Wall_Dun_3;
         public RuleTile _Wall_Boss;
     }
     
     [Serializable]
     public class Tile_Layer {
         public Tilemap _Barrier;
         public Tilemap _Ground;
         public Tilemap _GroundOverlay;
         public Tilemap _Obsticles;
         public Tilemap _ObsticlesOverlay;
     }
 }

I have attempted several other methods of trying to get the _TileLayer to locate an item from the Tile_Layer class that matches the string of the input but nothing I have tried is working. The line above it tested just fine when explicitly pointing to "_Ground", but I would prefer the line to be dynamic. the same would be true for "_GroundFields" in that same line, but I'm sure solving 1 issue will solve the other.