I've always had FALD disabled with games because it adds to the input latency. Even without local dimming, the TV's contrast and black levels are pretty solid. In fact, local dimming on this TV has the drawback of crushing some of the finer detail in dark scenes
Don't prefer to have it on in movies/TV shows either, as it's pretty jarring to see certain zones of the screen have their backlight disabled while others have it enabled during dark scenes, particularly if a bright object is moving within dark scenery. There's a reason why the Netflix calibrated mode on this TV seemingly disables local dimming