I don't think an OLED for your usage is necessarily the best route, if Warzone is your main/only game you probably want a good IPS or even VA (I'm not keen, but others get on) with low latency and high refresh. The X34 was amazing back when it launched, but tech does move on, I feel you might be looking for higher refresh/better latency and improved visuals with the latter being less important.
Single player games with gorgeous visuals are why I like OLED monitors, usually much slower paced to boot. That's not to say they can't be grand for that, but if my focus was an FPS for performance? A decade is a long time, you might be surprised at how good modern IPS/VA panels look on top of their responsiveness. I wouldn't spend £500-600 on an OLED for Warzone mate.
