I had more flickers back in the day and reported here about white flickers in Google Chrome when the hardware acceleration is on, that got fixed on the driver 23.5.2 but the discord remained. Turning off Discord HW acceleration "fixes" it. It happens very rarely, like once or twice a day, however, I managed to see what happens exactly. Before I thought it was the whole screen flashing white, but after taking a recording of the screen with instant replay, I can see for a single frame the Discord app goes full white and comes back. The issue is still present in the 23.10.1 driver.
the whole white section is actually discord.