I digged a little more into the error, it looks like when I had an Enum type to the CustomType that I'm trying to use SwiftData doesn't like that? I still don't understand the error though.

Interesting, my enum error is fixed with Xcode 15 Beta 3, you should check if yours is fixed to.

I'm also having the same issue on Xcode 15 beta 6 on macOS Ventura on an iOS 17 device running beta 6.

This issue is fixed for me on beta 7 of iOS 17 and Xcode 15.

Interesting, I thought I was doing something wrong or missing something since I'm more of a newbie developer. I might take time to submit that as feedback if I see this working on iOS 17.

Oh!! I remember reading that it was an enum in the docs but my brain didn't think of using a Switch statement like this 🤦🏼‍♂️. Thank you for your response. This answers my question.