Rydberg atomic receivers hold extremely high sensitivity to electric fields, yet their effective 3-dB baseband bandwidth under conventional electromagnetically induced transparency (EIT) is typically constrained to tens to a few hundreds of kilohertz, which hinders wideband wireless applications. To relax this bottleneck, we investigate a six-wave mixing (SWM)-based Rydberg atomic receiver as a wideband radio frequency (RF)-to-optical quantum transducer. Specifically, we develop an explicit baseband input-output model spanning from the probe input to the output light field. Based upon this model, a closed-form 3-dB bandwidth expression is derived to expose its dependence on key optical and RF parameters. We further quantify the linear dynamic range by employing the 1-dB compression point (P1dB) and the input-referred third-order intercept point (IIP3), unveiling a communication-compatible characterization of the bandwidth-linearity trade-off. Finally, our numerical results demonstrate that, given identical optical driving conditions, the SWM configuration increases the 3-dB baseband bandwidth by more than an order of magnitude compared to the EIT-based counterpart, while retaining comparable electric-field sensitivity and revealing a broad, tunable linear operating region.