I have to deal with complex DTOs but would still like to edit a property using two way binding.

// BAD
<my-component [(value)]="myfield.propertya.propertyb" />

If I do so, I would mutate the original object. Angulars change detection would not understand the change.

Doing it correctly as an immutable update, I need to write an update method for each property:

// GOOD BUT BULKY
<my-component [value]="myfield.propertya.propertyb"
              (valueChange)="changePropertyAPropertyB($event)" />

changePropertyAPropertyB(value) {
    myfield = { ...myfield, propertya: { ...myfield.propertya, propertyb: value } }
}

// or simplified with immerjs
changePropertyAPropertyB(value) {
    myfield = produce(myfield, draft => { draft.propertya.propertyb = value })
}

Is there a way to do so without an extra method for each property?

With model signals I still have the same problem.

NGRX Signal State allows deep reads like [value]="mySignalState.propertya.propertyb()".
But updating it, I still need a to create a bulky patchState method

changePropertyAPropertyB(value) {
    patchState(mySignalState, 
        (state) => ({ propertya: { ...state.propertya, propertyb: 'Jimi' } })
    );
}

Is there a concise and simple way that works well with the angular change detection?