Dash has a displacement setup in its UE5.3 and 5.4 Megascans materials by default. (Not for the Poly Haven assets)
To use it, make sure that the mesh you're applying the material on has nanite enabled. If it is not turned on, you can search for nanite in Dash to find an action that will turn it on (Actor Switch Nanite), on your selected mesh.
Then also make sure that nanite tessellation is enabled in UE5. You can do that by running enable nanite tessellation command in the Dash prompt bar, if you haven't enabled it already. Once that's done, drag and dropping any material on your mesh will have tessellation working. You can then also adjust it from within our Material Edit tool.
If your material doesn't have displacement still, then make sure to delete the Megascans asset from the UE Content browser, just so Dash can reimport it when you drag it in from the Dash Content Library.
Another thing that is important is that the mesh you are trying to Displace, has to be a static mesh, it can't be a Procedural Mesh, like the Dash Terrain. You can convert a Procedural Mesh to a Static Mesh by searching for "Convert to static" in Dash And after you have done this, remember to use the action "Actor Switch Nanite"