Don't game on OLEDs. The burn in is a real threat to your screen.
I assume that model number is your country's version of the XBR55X900E, in which case I say get that.
Not true, I've been gaming on OLED for the past 6 months, sometimes for 10 hours straight and my television is (so far) doing more than fine.
What you should not do with a self emissive set such as an OLED TV is let a frozen picture on for hours, like pausing a screen and letting it like that for a long time and if there is nothing bright in the picture it shouldn't really be an issue, but out of caution you don't let it on for long. Don't EVER let a bright picture paused for long cause that could imprint on your screen.
So obviously don't use an OLED screen as a computer monitor cause those tend to stay on the same image for very long, like the toolbar at the top of some programs stays on sometimes for the entire time your computer is on. (Without moving cause if the toolbars moved even a little it would not be a problem but they don't move and stay exactly to the pixel at the same place)
But as a TV to game and watch movies and shows, it's perfect. Careful if using Twitch on it though, as some streamers don't go full screen and you often got the left or right part of the screen with a space for chat and that space does not move at all and if you do that for many hours at a time, well, I don't advise it.