It makes sense comparing Onkyo TX-RZ920 vs Onkyo TX-8020 because they both are able to give some premium features.
A significant difference between the receivers in the number of channels, Onkyo TX-RZ920 has 9.2 versus 2.0 for Onkyo TX-8020. Regarding power, then TX-RZ920 has such a W/Ohm ratio - 135/8, 175/6 when TX-8020 has a power of 90/6. The THD is 0.04% for the TX-RZ920 but 0.03% for the TX-8020.
Characteristics of digital to analog converter (DAC) are different, AK4490 384 KHz/32-bit for TX-RZ920 and 192 KHz/24-bit for the TX-8020. Only the TX-RZ920 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Only the TX-RZ920 has Bluetooth support. The Onkyo TX-RZ920 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Only the TX-RZ920 supports Spotify. Only the TX-RZ920 provides HDMI signal transmission in standby mode. The TX-RZ920 can scale the input HDMI signal, unlike the TX-8020. Dolby Vision technology found support only on the TX-RZ920. Only the TX-RZ920 supports HDMI Audio Return Channel (ARC). The HDMI eARC is available only on the TX-RZ920. Of the two receivers in our comparison, HDMI CEC is present in only the TX-RZ920. These compared receivers have a built-in phono stage for connecting a vinyl player. An ECO mode is not present in each of the AV receivers. The setup assistant will help you configure Onkyo TX-RZ920.
Only the TX-RZ920 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-RZ920.
The Onkyo TX-RZ920 is better receiver in this comparison. Check Onkyo TX-RZ920 price