Lagging in the game

hello mojang, I want to make a complaint about minecraft 1.16.101 version. How come since I played in that version, always framing and loading old times in my world, when I enter my sister's world on the same device, it's fast, but in my world and when I want to create a new world, the loading is always long, if I enter realms, it goes well on the default graphic, please lighten it as soon as possible so that I can play comfortably