The estimate of stellar metallicities (Z*) high-z galaxies are paramount importance in order to understand the complexity dust effects and reciprocal interrelations among mass, attenuation, age, metallicity. Benefiting from uniquely deep FUV spectra >500 star-forming at redshifts 2<z<5 extracted VANDELS survey stacked bins mass (M*) UV continuum slope (beta), we their Z* photospheric absorption...