Your "Display" is not like your Desktop.
Many of the Graphic Cards today rival specs of the very core of the computer systems they are in. They have massive amounts of DDR-5 RAM, massive multiple high speed data lines (3,800,000,000 bps or 3.8 Gbps), and thousands of compute cores that assist with the computations of lines, triangles, shaders etc.
Your display does not. It has a limited amount of RAM just enough to store 18-bits of color values for each pixel (of which we use two-bytes worth in the 16-bit 565 format), it has a limited processor embedded in the screen somewhere under the pane, and it has two low speed data lines that because of its TTL nature and being susceptible to interference, can cause data loss at higher speeds. The Rx/Tx data lines provide 9600 bits per second (otherwise known as your baudrate) and if lucky we can get up to 115,200 without data loss.
Compared to the desktop graphics card you are using as you program your Arduino, it has much lower capabilities. Realizing this early in the process will drastically improve your game.