If your external monitor is flickering after your connect your apple mac that has apple silicon. And it didnt flicker if you connect an intel or other pc's. I have a solution for you

Problem

1. the issue is due to the how apple silicon gpu's render images on certain monitors.
2. i recently upgraded my old intel based mac book pro with m4 mac mini - great upgrade
3. but the external monitors that were working properly earlier with the intel cpu mac was now showing flickering.
4. the problem is that this flicker is not constant but it flickers when there are some shading of gray or transparency
5. the issue i found out after a lot of research is that its because of how the apple gpu's render.
6. apple gpu's use some tech call DCI dithering, which works great on apple monitors like the one on the laptop or apple's own monitor or some apple supported ones like LG Ultrafine.
7. but on mine like BenQ, this dithering makes it look very strange and uncomfortable to view

Solution

1. You can turn off the dithering using some software like BetterDisplay or StillColor
2. BetterDisplay - https://github.com/waydabber/BetterDisplay - 14 day trial but it works and has a bunch of othe goodies
3. StillColor - https://github.com/aiaf/Stillcolor - free, also works
4. In both these tools you can turn off the GPU dithering and this problem vanishes and your eyes will thank you
5. On Better Display -> choose the monitor, choose color mode and turn off GPU Dithering
6. On StillColor -> follow the instruction, you just run it once and then you can check if the dithering is turned off or not

Bonus

1. I found that you can set your monitor color profile to Display P3 and its matches you macbook's screen in color and tone, wonderful. Much better color profile than the default i had been using till now.
2. Visit this site to check the before and after effect of your change http://www.lagom.nl/lcd-test/ wonderful site to geek out on you monitor.