Capture and save large mode of minimap as png file to the game root folder. Spend big time messing with this code. Hope it will save someone's time.

MapCapture.cs

using System.ComponentModel;
using System.IO;
using System.Threading.Tasks;
using BepInEx;
using JetBrains.Annotations;
using UnityEngine;
using static UnityEngine.Object;

[PublicAPI]
public static class MapCapture
{
    [Description("Capture and save large mode of minimap as png file to the game root folder.")]
    public static async Task CaptureAndSaveMap()
    {
        var mode = Minimap.instance.m_mode;
        Minimap.instance.SetMapMode(Minimap.MapMode.Large);
        await Task.Yield();
        Minimap.instance.SetMapMode(mode);

        var material = Minimap.instance.m_mapLargeShader;
        var savePath = Path.Combine(Paths.GameRootPath, "map.png");
        var width = material.mainTexture.width;
        var height = material.mainTexture.height;

        var renderTexture = new RenderTexture(width, height, 24);
        renderTexture.name = "Temp_MapRenderTexture";
        renderTexture.enableRandomWrite = true;
        renderTexture.Create();

        var tempQuad = GameObject.CreatePrimitive(PrimitiveType.Quad);
        tempQuad.GetComponent<MeshRenderer>().material = material;

        var tempCameraObject = new GameObject("Temp_MapCamera");
        var tempCamera = tempCameraObject.AddComponent<Camera>();
        tempCamera.targetTexture = renderTexture;
        tempCamera.orthographic = true;
        tempCamera.orthographicSize = 0.5f;
        tempCamera.nearClipPlane = -1f;
        tempCamera.farClipPlane = 1f;
        tempCamera.clearFlags = CameraClearFlags.Color;
        tempCamera.backgroundColor = Color.clear;

        tempQuad.transform.position = tempCamera.transform.position + tempCamera.transform.forward;
        tempQuad.transform.localScale = new Vector3(1, 1, 1);

        RenderTexture.active = renderTexture;
        tempCamera.Render();

        var texture = new Texture2D(width, height, TextureFormat.RGB24, false);
        texture.name = "Temp_MapTexture";
        texture.ReadPixels(new Rect(0, 0, width, height), 0, 0);
        texture.Apply();

        var bytes = texture.EncodeToPNG();
        File.WriteAllBytes(savePath, bytes);

        RenderTexture.active = null;
        DestroyImmediate(tempCameraObject);
        DestroyImmediate(tempQuad);
        renderTexture.Release();
        DestroyImmediate(renderTexture);
        DestroyImmediate(texture);
    }
}