Shadermods, like Iris, Oculus, Optifine are only partially supported. Shaders only work with the fallbackrenderer active. This gets activated by default if loaded with Iris and Oculus. This can be deactivated in the Config or force activated if othermods create issues with Truly Modulars Rendering
Truly Modular uses an Automatic compat by default, this means most mods Swords and Materials should get picked up, dedicated compat is possible through datapacks. You can use the MaterialHelper Website to make compat datapacks yourself
FAQ:
What Launcher is this for? Forge? Fabric?
Both, check the jars
Backport to older versions?
is not planned. There are many features in Truly Modular which have a significantly higher priority than backporting. Once the list of ideas is smaller we might consider backporting.