i was about to return my new monitor, but discovered that Apple computer only output composite signals (YUV). so not RGB like most monitors are expecting. i guess you need a “special”, “Apple approved” monitor.
fix the disgusting flickering and artifact using this
https://gist.github.com/GetVladimir/c89a26df1806001543bef4c8d90cc2f8#alternative-terminal-commands-to-force-rgb-color-output-on-m1-and-m2-based-macs-and-workaround-for-losing-rgb-color-after-waking-up-from-sleep
that completely fixed it for me on my Philips 328E 1CA monitor.