Draw tilemap with Texture2D.SetPixels: Performance and Memory?

People often draw Tilemap with Mesh, but this method has a problem that you can only use one Tileset each layer, so I'm thinking of using Texture2D.SetPixels and SpriteRenderer instead of Mesh Renderer.

I'm wondering that if this method has problems with performance or not. And for the memory/performance issue, I don't know if I should render the Tilemap in Start or Awake method of GameObject.

Please give me some advises, thank you.