I’m here trying to repurpose a lethal company mod and using Harmony to patch the files, but when I try to build the dll file on vsc i keep getting this same error.
I’ll send the code. The error occurs at line 65 to 68.

using System;
using BepInEx;
using BepInEx.Configuration;
using BepInEx.Logging;
using GokuBracken.Patches;
using HarmonyLib;
using UnityEngine;

namespace GokuBracken.Core
{
    // Token: 0x0200000B RID: 11
    [BepInPlugin("", "", "")]
    public class GokuBrackenBase : BaseUnityPlugin
    {
        // Token: 0x1700001A RID: 26
        // (get) Token: 0x0600004C RID: 76 RVA: 0x000022D6 File Offset: 0x000004D6
        // (set) Token: 0x0600004D RID: 77 RVA: 0x000022DD File Offset: 0x000004DD
        internal static GokuBrackenBase Instance
        {
            get
            {
                return GokuBrackenBase._instance;
            }
            set
            {
                if (GokuBrackenBase._instance == null)
                {
                    GokuBrackenBase._instance = value;
                    return;
                }
                UnityEngine.Object.Destroy(value);
            }
        }

        // Token: 0x1700001B RID: 27
        // (get) Token: 0x0600004E RID: 78 RVA: 0x000022F9 File Offset: 0x000004F9
        public static ManualLogSource LogSource
        {
            get
            {
                return GokuBrackenBase.Instance.Logger;
            }
        }

        // Token: 0x1700001C RID: 28
        // (get) Token: 0x0600004F RID: 79 RVA: 0x00002305 File Offset: 0x00000505
        public static ConfigFile ModConfig
        {
            get
            {
                return GokuBrackenBase.Instance.Config;
            }
        }

        // Token: 0x06000050 RID: 80 RVA: 0x00002DD8 File Offset: 0x00000FD8
        private void Awake()
        {
            GokuBrackenBase.Instance = this;
            base.Logger.LogInfo("Initializing config...");
            ConfigManager.InitializeConfig();
            base.Logger.LogInfo("Loading asset bundle...");
            Assets.PopulateAssets();
            base.Logger.LogInfo("");
            base.Logger.LogInfo("");
            this.Harmony.PatchAll(typeof(GokuBrackenBase));
            this.Harmony.PatchAll(typeof(EnemyPatches));
            this.Harmony.PatchAll(typeof(TerminalPatches));
            this.Harmony.PatchAll(typeof(RoundManagementPatches));
        }

        // Token: 0x04000018 RID: 24
        private static GokuBrackenBase _instance;

        // Token: 0x04000019 RID: 25
        private readonly Harmony Harmony = new Harmony("");
    }
}

the specific lines that error are:

            this.Harmony.PatchAll(typeof(GokuBrackenBase));
            this.Harmony.PatchAll(typeof(EnemyPatches));
            this.Harmony.PatchAll(typeof(TerminalPatches));
            this.Harmony.PatchAll(typeof(RoundManagementPatches));

note that EnemyPatches, TerminalPatches, and RoundManagementPatches are cs files.
I tried using Assembly.GetExecutingAssembly and GetCallingAssembly, but it still gives me a similar error.