Ventura not supporting 5120x1440

Hello amccrob,

Welcome to Apple Support Communities!

We want to help with the video options for your Mac mini.

This Apple Support page has the technical specifications for the Mac mini (M1, 2020): Mac mini (M1, 2020) - Technical specifications

"Video Support

• Simultaneously supports up to two displays:
• One display with up to 6K resolution at 60Hz connected via Thunderbolt and one display with up to 4K resolution at 60Hz connected via HDMI
• Thunderbolt 3 digital video output supports
• Native DisplayPort output over USB‑C
• Thunderbolt 2, DVI, and VGA output supported using adapters (sold separately)
• HDMI display video output
• Support for one display with up to 4K resolution at 60Hz
• DVI output using HDMI to DVI Adapter (sold separately)"

You can use these steps to change the resolution to one of the available options:

"Set the resolution for a connected display

If you have more than one display, additional resolution options are available after the other display is connected.

1. On your Mac, choose Apple menu  > System Settings, then click Displays  in the sidebar. (You may need to scroll down.)
2. Select your display on the right, click the pop-up menu next to Resolution, choose Scaled, then select the resolution you want to use.
3. You may be able to turn on “Show all resolutions” to see additional resolutions for the display."

This Apple Support page has the full details: Change your Mac display’s resolution - Apple Support

We hope this helps to adjust your display to the appropriate resolution.

Cheers!