When overriding the TextTheme without any changes, the text color gets updated to color white in the light theme

Question

I want to extract the TextTheme customization in it's own class so I have a single point where I configure the text.

In this class I have tried the following with the same result:

var lightTextTheme =Typography().black.copyWith();
var darkTextTheme = Typography().white.copyWith();
OR
var lightTextTheme = TextTheme().copyWith();
var darkTextTheme = TextTheme().copyWith();

My ThemeData is configured as follows:

  ThemeData lightMaterial3 = ThemeData(
    brightness: Brightness.light,
    useMaterial3: true,
    inputDecorationTheme: inputDecorationTheme,
    primaryTextTheme: lightTextTheme,
    textTheme: lightTextTheme,
  );
  ThemeData darkMaterial3 = ThemeData(
    brightness: Brightness.dark,
    useMaterial3: true,
    inputDecorationTheme: inputDecorationTheme,
    primaryTextTheme: darkTextTheme,
    textTheme: darkTextTheme,
  );

And I use the TextStyles as follows:

  TextStyle labelSmall = Theme.of(Get.context!).textTheme.labelSmall!;
  TextStyle labelMedium = Theme.of(Get.context!).textTheme.labelMedium!;
  TextStyle labelLarge = Theme.of(Get.context!).textTheme.labelLarge!;

When changing the Theme, the TextTheme doesn't get updated, therefore, when I switch from dar to light, the text remains white.