I can confirm the game switches to 1080/120p on HDMI 2 (Can't use HDMI 4 as that's the only one that has ARC so my Soundbar is using that port), but you HAVE to set the PS5 to choose Performance over Resolution in the PS5's settings. Gutted i can't play 4K/120p or even 1440/120p as it's super smooth!There is no way to just set PS5 to 120Hz like there is on Xbox. You need to have a game that supports 120Hz and go into PS5's 'Game/App Settings' and select 'Game Presets' and you can have PS5 choose performance or resolution modes in games as a default. That's currently the only way to play any game in 120fps. I don't own any 120fps games on PS5 to try. Fortnite is free so I guess I could download it to see what resolution the Q70R displays at 120Hz on PS5.
*EDIT: After trying Fortnite, PS5 switches to 1080p120 (using HDMI 4 on Q70R). No support for 4K120 or even 1440p120 that is supported on Xbox. The good news is, unlike Xbox, PS5 still supports HDR at 1080p120.
I wonder what other PS5 games support 120hz..