It seems like you're encountering issues with the shaders when using Spine with the Universal Render Pipeline (URP) in Unity. The pink color indicates that the shader is not compatible with URP. To resolve this, ensure you are using the correct URP-compatible shaders provided by Spine. You should use the Universal Render Pipeline/Spine/Skeleton Lit shader for your materials. If the sprite is invisible with this shader, double-check that your URP settings are correctly configured in Unity's Project Settings under Graphics and Quality. Make sure the URP Asset is properly assigned, and that the lighting settings are configured to interact with the Spine shaders. Additionally, ensure that the Spine URP Shaders UPM package is up to date, as older versions might not be fully compatible with the latest Unity or URP versions.

Yimec It is expected behavior that the Spine/Skeleton Lit shader will be pink in URP projects.
as you have seen, since the shaders for the built-in pipeline are not available in projects using URP.
If you want to use the URP Shaders Extension Package, check that the example scenes for URP are displayed correctly after installing it. Example scenes for URP shaders can be imported from the package manager:

(In my screenshot, the button says "Reimport," but if you haven't imported yet, it should say "Import".)

If the appropriate URP assets have been set up within Project Settings, the example scene should look like this:

The Raptor skeleton in this scene uses the Universal Render Pipeline/Spine/Skeleton-lit shader, so this will help you to see what it would look like if you applied this shader: