Look into replacing MvxViewModel and derivatives
I would love to do composition over inheritance for anything MVVM related, such that consumers of MvvmCross can choose to use their own implementation of INotifyPropertyChanged, use CommunityToolkit or perhaps ReactiveUI or whatever they feel like.

Instead of being forced to inherit from MvxViewModel or similar, just because it contains some lifecycle methods that are convenient.

To receive the lifecycle callbacks, could also be a composition detail, such as inheriting from a IMvxViewModelLifecycle interface.