How to Disable the World Loading Screen Entirely
What This Mod Does by Default
On newer game builds, this mod already skips the "Loading Terrain" screen when you change worlds. Instead of watching the dirt-texture screen fade in, you drop straight into the world. This is the intended behavior and needs no configuration on those builds.
When You Still See a Flash
If you notice a brief screen flash when joining a server, that is usually the resource pack loading screen, not the world loading screen. The mod shortens that too by stripping the forced fade-in and fade-out and the minimum on-screen time. On a fast pack, the screen may appear for only a frame or not at all.
Checking It Is Working
1. Join a singleplayer world and note whether the loading terrain screen appears.
2. Join a multiplayer server and compare.
3. Load a resource pack and watch how quickly the pack screen disappears.
If the world loading screen still lingers, another mod or a client setting may be re-adding it. Check your other performance or UI mods for options that force a loading screen, and disable those first.