We are having a similar issue. We tracked it down to when we are updating @Published vars in our view models, but have not found a work around. We are not having the app freeze, but see the CPU spiking over 100% then staying pegged at 100% until we close the app.
If we run the app on a device that's at ios 17.6, no issues. Only when we run on an iOS 18 device do we see the problem.