I have implemented it with a ViewHandler Mechanism from Maui.
You only need to add a GameView which is a Maui View to your ContentPage.
Inside the ViewHandler the Game will be instantiated and initialized.
Each platform has it’s own ViewHandler, actually I am working on Mac Catalyst, but not sure if it is possible. Android and iOS works really well.
So and you can then insert a few UI Elements directly after the GameView, the UI-Elements are rendered as an overlay over the game view and the UI-Controls are clickable and can execute some MVVM Logic or code behind methods.