Denon and Marantz will add HDMI 2.1 to these older receivers for $600
Denon AVR-X2800H 7.2 Ch AV Receiver | Selby
Report: latest AVRs from Sony, Denon / Marantz, Yamaha, etc. have a bug in the HDMI 2.1 chip - unable to pass through the 4k120hz HDR10 signal (german article) : r/xboxone
Denon announces first HDMI 2.1 receivers for 8K60, 4K120 pass-through - FlatpanelsHD
Denon AVC-X4700H Review - Planet HiFi
AVC-X3800H
Xbox Series X HDMI 2.1 Issue Gets a Fix - 8K Association
Denon announces refreshed 8K AV receiver lineup with loads of HDMI 2.1 ports | TechSpot