Radio and (sub)mm spectral energy distributions (SED) of RL quasars reported in this work. We show the continuum emission at 1 mm from our ALMA Band 7 observations (orange circles) and the relative best fit of the modified black body dust emission (black line). In the case of J2228+0110, we could retrieve only upper-limits from our ALMA Band 3 data and we show the corresponding limits on its dust emission with a shaded grey area. All modified black-body are calculated with T = 47 K and β = 1.6 (see Sect. 4.4). For each quasar, we report the radio observations obtained from a collection of literature data (see Sect. 4.3 for references). For J0131-0321, J1034+2033, PSO352-15, J2228+0110 we show (broken) power-law radio emissions, with slopes (α) derived from fits in the literature. For PSO055-00, PSO135+16, we assume a median high−z slope value (see Sect. 4.3). The solid light blue lines are the measured power-law functions, while we report with dashed lines the extrapolation to lower and higher frequencies. The light cyan lines highlight the regions encompassed by the 1σ uncertainties on the power-law slopes. We show with light blue empty circles the flux extrapolated from the synchtrotron power-law functions at the ALMA frequency targeted in this work.