Use hintable instead: it allows you to access/set field values as if there were properties, in reality, the properties are virtualized based on phpdoc above the model class
to use it, you need to define each property incl. the type, above your model classes, see ui demos or https://github.com/mvorisek/atk4-hintable-mirror/blob/develop/tests/Data/Model/Standard.php and https://github.com/mvorisek/atk4-hintable-mirror/blob/develop/tests/Data/HintableModelArrayTest.php

the advantage is much shorter code which supports refactoring incl. type checking, field names are refactorable using brutal magic too like $model->fieldName()->customer_name 😉

also all traversing is then as simple as $customer->address->city instead of $customer->ref('address')->get('city')