How can I use displacement in 5.4 to add a digging effect in the landscape?

I’m glad it works for you! The RVTs are definitely more towards polish than gameplay components, so it’s totally fine just to deform the mesh with just WPO. If your meshes are well blended, you may not even need the ground blending tech. The footprints setup is also really good at teaching you to modify RVTs at runtime, and can be used for a myriad of things outside of footprints, so it’s a good thing to learn even if it’s not applicable to your current project. Have a great day!