If you are connecting from a DVI (or sometimes DP) port on your GPU Card--via an adapter cable--to an HDMI port on your monitor and the display looks magenta, you can fix the issue in the monitor control panel. Go to the monitor Color Settings; select Input Color Format; change from RGB to YPbPr. That should solve the problem.
Connect one 4k monitor to the DP port.
Connect one 4k monitor to HDMI port.
Connect two 4k monitors a Sonnet Thunderbolt 3 to Dual DP or Dual HDMI adapter connected to the Thunderbolt 3 port.
macOS 14 (Sonoma) and macOS 15 (Sequoia) will crash when an eGPU is hot disconnected. It will work fine if you connect or disconnect when the computer is shut down. Sonnet has filed a bug report with Apple.