如何将选定的角度下拉值绑定到标量值的Observable？

I have an angular material select component and I would like to bind the selected value of the dropdown to an Observable of scalar from firebase. I would like to do this without unwrapping the observable in component. It looks I cannot bind the value using async pipe. The code below throws an exception because the value of mat-select cannot be bound to "uiStateSvc.currentClient$ | async".I have an angular material select component and