Sorry,it can not support extended mode,this splitter hdmi only support mirror mode.
Yes,this HDMI 2.1 splitter can work well 4K@120Hz RGB 4:4:4 WITH PS5 and XBox one
when the resolution is 8K/4K@120Hz, input/output up to 10ft(3m), When the resolution is 4K@30/60Hz, input/output up to 16.5ft(5m).
Yes,this hdmi splitter could help you enjoy HDR 10+,dolby vision,VRR,ALLM,QFT and 7.1 atmos
When your HDMI input source(such as PS5/XBox one and PC) support 4K@120Hz or 8K,please you set the video out of hdmi source with 4K@120Hz or 8K.then you will get better image