As shown above, the subpixles in the Dell S3225QC QD-OLED form a square with green on the top, a larger red pixel in the lower left, and smaller blue

So OLED has a definitive drawbacks for some displays, but

This gets at why OLEDs make great TVs and gaming monitors. The contrast is outstanding, color is excellent, and high refresh rates are ideal for moving images and fast-response games. [...] They also work great on small devices like phones where the pixel density is so high that fringing is too small to see.

But on desktop monitors for still things — text and fine lines — OLEDs currently just aren’t great; I guess that’s why office and productivity type monitors are still LCDs.