CustomTitleScreen
This modification is specifically designed for the Fabric loader and is incompatible with Forge.
With CustomTitleScreen, you gain complete control over the appearance of Minecraft's loading screen. You can not only set any background image but also change the positioning of interface buttons and add your own custom elements.
To install a custom background, simply place a file named background.png in the config/cts/ directory. To adjust other screen parameters, launch the game with the mod installed and edit the configuration file - the settings will appear automatically.