In my role on the developer education team at MongoDB, I wrote and maintain a SwiftUI #iOS app - a basic task tracker - that serves as a template app to build on to get started with Realm Database and Device Sync.
I regularly want a local SwiftUI Realm app to test new features and functionality, as well as PoC small app ideas, so I've made a non-Sync version of this app template. It's intentionally minimal in styling, model, and functionality to make it easy for you to adapt and build with it.
If you might find something like this useful, check out my little summary on DEV Community with some screenshots & info: https://dev.to/dacharyc/realm-swiftui-template-app-5hg8
Or if you want to take a look at the GitHub repo directly, it's here: https://github.com/dacharyc/realm-swiftui-local-client
For now, I can easily branch from here to spin up new versions of the app to test out different features and PoCs. But maybe someday soon I'll spend the extra time to make this a template in Xcode.