Installed Ventura

The title of this post should be: Having problems with external SSD disk containing Ventura + OCLP.

I picked the model for my iMac in settings, I created a macOS Installer, and then built/installed OpenCore. Ventura was installed onto an external SSD using this USB installer and I got through all of the setup screens (e.g. language, time zone, etc.).

I power cycled the computer while pressing the option key and selected the external drive that had Ventura installed (using the OpenCore Mac OS USB installer). The screen with the circle with a line through it showed up (which means that the startup disk contains a Mac operating system that the Mac can not use).

What did I do wrong? Note: I installed Ventura with OCLP onto an external SSD using a MacBook. I am trying to use the external SSD as my startup disk on my iMac. This should work since I selected the model for the 2014 iMac in the OCLP settings (imac 15,1).