Assuming you aren't sitting 2 feet from the TV and aren't bothered about sync tech..... 1080P @ 120HZ on the 2017/2018 LG models is fantastic and should fix any of the issues with input lag etc. that most people always dislike about 60HZ displays.
Myself and a number of other friends have commented on how disappointing 4k is compared to 1080P in media and more so game related content (unless the media/game is specifically made for 4k or/and using proper 4k assets) when sat the appropriate distance of 7-8 feet from the TV, so much so that the only time my TV ever switches to 4k is when viewing content on netflix, although I might even start to limit the res. to just 1080P for that now as well) EDIT: And of course, UHD films, but I get these solely for the HDR part.
Also, the nvidia 65" display will be far more than £2k, the last price rumour was £5k iirc (especially when these 27" displays are going to be costing £2k)
The assumption seems to be that everyone wants to game on a 60hz OLED TV but I don't, at all. Picture quality is amazing but pretty much everything else is terrible. I tried it for an hour and hated it. I thought these big G-Sync TV's were going to be way more than 2k but if they hit at about that I'd consider it (unless there is a OLED 4k 120hz TV with G-sync planned).
Agreed it really needs to be a TV recommended viewing distance away rather than using it as a monitor which i definitely wouldn't recommend. I use mine from approx 8-10 feet. And love it.
Although it does not get 100% use though, as i do like my 165hz for fps and k+m, hense why i wouldn't recommend the OLED soley as a monitor. Just too close.
Haven't even thought about sync tech on mine has been great. I haven't tried mine with a mouse yet but use it with a controller at 4k 60hz and the input lag is plenty low enough. Can't notice the difference between that and my monitor with a controller anyway, even at 30hz on my ps4 pro i haven't even noticed it.
I've had 4k 27" in the past and there isn't that much of a difference between that and 1440p. More of a difference from 1080p to 1440p.
Considering its price tag and the system you would need to even attempt to target 4k 144hz (1180Ti SLI) most likely. And the fact it's only 27" really needs to be 32"-34"ish at the very least to get the best from 4k close up.