You may have to import those assets in Unreal, then convert them to static mesh independently from Bridge. The term in Unreal is “static mesh”, whereas the term in a different application could be “mesh” or “model” or something else. Those assets are more like a brush, or a prefab…they’re still a 3D object / actor you place in the scene. However, they’re not defined as a static mesh in Bridge. Unreal puts the emphasis and technical meanings of the assets as static meshes, so try exporting or downloading from Bridge and importing to Unreal to a specified folder in the project. Then convert to static mesh.
In the dialog for it, select “Import Normals and Tangents” to maintain those used in the original asset, or select “Compute Normals” to let Unreal Engine compute new normals for them. I can’t say which is better or correct, though I would attempt to import the existing normals and tangents first. Enable “Convert Scene” too, on import, and enable Unreal’s coordinate system for the imported assets, and select Unreal’s scale units. If it’s too small, disable Unreal scale units or disable “Convert Scene”. It’s a trial/error process.