Different black levels between PS4 Plex client and LG TV Plex Client



I recently purchased an LG OLED 55B6V and upgraded to a PS4 Pro.

I've always used my PS4 for Plex, and noticed that when watching content, very deep black levels with little nuance to shading. I took this to just be the nature on OLED TVs (note, TV has been professionally calibrated).

Recently, I happened to use the native LG Plex app to continue watchign something (as I wanted to leave my PS4 running to gather Moolah in "Vostok Inc" - a great game BTW).

The difference was night and day!!! The same plex stream on the LG Plex app was stunning, whilst on the PS4 I was struggling to see anything in the same dark scenes.

Does anyone have any ideas what could be causing this? I've compared Plex settings briefly, and have noticed that “Maximum H.264 Level” is 5.1 on LG, and 4.1 on PS4 - does that make a difference? Or is this possibly another Plex setting I've missed? Or is this due to something to do with the Playstation itself, and any limits it has, or somethign special the LG is doing?

I'd like to continue to use Plex via the PS4 is possible, as have a bluetooth headset and means can watch films when missus goes to bed - if can't resolve, i'll probably need to get another bluetooth headset for using with the TV and would like to save myself the expense.

Any help appreciated!!!