14" M1 Pro Macbook Pro - HDMI external screen Flickering/Flashing black periodically

Hello DanRegueira,

Thanks for posting in Apple Support Communities. We understand that you are experiencing an issue with flickering/refresh rate on your external display.

Most newer HDMI cables are high speed, but we would recommend testing another cable or via USBC to rule out the cable causing the issue.

You may also want to see if you need to adjust the refresh rate or built-in controls on the external monitor itself.

Cheers!

HDMI cables you want for HDMI-only Monitors (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

HDMI computer output is bandwidth limited. HDMI output is suitable only for DIRECT connection to a display's HDMI input, PROVIDED you use a Premium High Speed cable with a certification tag.

it can NOT be converted to another interface using ordinary, inexpensive adapters, and if you did actually manage get it adapted to something else, the supported resolutions and refresh rates would be pitiful.

Use DisplayPort family or its support built into ThunderBolt or USB-C.