I made this on accident, maybe someone finds the useful (Use RenderMeshIndirect for speed)

UnoptimizedTVNoise.cs

using System.Collections;
using UnityEngine;

public class NoInstancing : MonoBehaviour
{
    private struct MeshData
    {
        public Vector3 offset;
        public Quaternion rotation;
        public Color color;
    };
    
    [SerializeField] private Material _material;
    [SerializeField] private Mesh _mesh;

    private short _gridSize = 64;

    private RenderParams _renderParams;
    private MeshData[,] _meshDatas;
    private Color[,] _oldColors;
    private Color[,] _newColors;

    private void Start()
    {
        _renderParams = new RenderParams(_material);
        _meshDatas = new MeshData[_gridSize, _gridSize];
        _oldColors = new Color[_gridSize, _gridSize];
        _newColors = new Color[_gridSize, _gridSize];

        //StartCoroutine(LerpToNewEmissionColors());
    }

    float alpha = 0f;
    private void Update()
    {
        alpha = alpha < 1f ? alpha + Time.deltaTime * 500f : 0f;

        for (int i = 0; i < _gridSize; ++i)
        {
            for (int j = 0; j < _gridSize; ++j)
            {
                if (alpha == 0f)
                {
                    _oldColors[i, j] = _newColors[i, j];
                    _newColors[i, j] = GetRandomEmissionColor(1f);
                }

                // Update mesh colors
                _meshDatas[i, j].color = Color.Lerp(_oldColors[i, j], _newColors[i, j], alpha);

                _renderParams.matProps = new MaterialPropertyBlock();
                _renderParams.matProps.SetColor("_EmissionColor", _meshDatas[i, j].color);
                // 

                Graphics.RenderMesh(_renderParams, _mesh, 0, Matrix4x4.Translate(new Vector3(i, j, 0)));
            }
        }
    }

    // It is important for one color to be 0
    private Color GetRandomEmissionColor(float colorIntensity)
    {
        float r = Random.Range(0, 2) * colorIntensity;
        float g = Random.Range(0, 2) * colorIntensity;
        float b = 0f;

        if (r == 0 || g == 0)
        {
            b = Random.Range(0, 2) * colorIntensity;
            if (r == 0 && g == 0)
            {
                b = colorIntensity;
            }    
        }
        
        return new Color(r, g, b);
    }
}