If you have a Dell monitor and an M-series chip from Apple, you may have encountered flickering issues with your monitor which — at times — can render it completely unusable. The issue appears to be fairly widespread and can affect a number of Dell model and Apple silicon chip combinations, and has been acknowledged by Dell.
The flicker is caused by the monitors LCD panel’s Image Compensation Algorithm (ICA) function repeatedly turning On and Off. The YCbCr Video generated from the Macs is at 17Gray level, it fluctuates between 15Gary and 17Gary. Hence it is repeatedly turning On and Off, the ICA which has a threshold setting of 16Gray.
The suggested solutions are to use Light mode, set the refresh rate to 30Hz, and use USB-c prioritization. In my case, I have a Dell P2721Q monitor alongside a Macbook Pro with an M1 Max chip and none of these suggested solutions worked for me.
What did work is to disable dithering with the application Stillcolor.
Download and install Stillcolor from the releases page, configure it to disable dithering, and hopefully this will solve your monitor issues like it did mine :).