Is your feature request related to a problem? Please describe.
Distant Horizons is a mod that adds LOD support to Minecraft greatly increasing render distant without a significant performance cost; It is recently adding support for Iris Shaders, while a stable version supporting them is not yet public, I think support should start to be considered.

Describe the solution you'd like
While I've not looked up how the implementation would work the two basic components should be a Compatibility Config and Blending support to extend the shader's rendering to included the LOD'ed chunks.
For more information there is a Shader Compatibility Gist and I'm sure people over on the Iris Shaders and Distant Horizons Discord would love to help.

Support is already on the way before this commit was made.