Chunk loading in Minecraft can be very jagged when they appear out of nowhere. With this mod, you can configure a nice animation for how chunks load in to your world.
I'm no longer maintaining this project. You can see why in my comment here, #9 (comment). A much better mod that does the same thing and more can be found here https://modrinth.com/mod/chunks-fade-in. As a side note, be kind to developers and creators who do things for free :)
Unfortunately the mod is incompatible with Sodium and OptiFine/OptiFabric at this time. I'd like to add support for them eventually though. I also assume that the mod is incompatible with many other rendering focused mods such as Canvas, though I haven't tested it.