The advancement of functional devices operating in multi-physical environments necessitates metamaterials with multi-functional co-modulation capabilities. Inspired by the nodal swelling and internodal tapering of Bambusa ventricosa, we developed diamond-type microlattice metamaterials (MMs) with biconical strut configurations and fabricated them via laser powder bed fusion. Integrating experimental characterization and numerical simulation, we systematically investigated the mechanical, fluidic, and thermal responses of these architected materials. Three functionally graded configurations, designated linear microlattice metamaterials (L-MM), quadratic microlattice metamaterials (Q-MM) and cubic microlattice metamaterials (C-MM), exhibited distinct scaling behaviors: L-MM followed linear Gibson-Ashby-type scaling with relative density, whereas Q-MM and C-MM showed nonlinear, weakly correlated mechanical responses. This divergence from conventional scaling attenuates the interdependence among strength, density, and transport properties, enabling independent optimization of mechanical and functional performance. These findings provide a design rationale for multifunctional metamaterials, with potential applications in aerospace thermal management and biomedical devices.