A single 1920x1080 framebuffer (which is a low resolution monitor in 2025 IMO) is 2MB. Add any compositing into the mix for multi window displays and it literally doesn’t fit in memory.
More like 6.2+ MB, or at least I'd sure hope that a FHD resolution is paired with at least a 24 bit (8 bpc) SDR color. And then there's the triple buffered vsync at play, so it's really more like 18.6+ MB.