Change TextInputEditText Hint Color

have you tried also these attributes for your AppTheme?

<item name="colorControlNormal">@color/primary</item>
<item name="colorControlHighlight">@color/warm_grey</item>      
<item name="colorControlActivated">@color/warm_grey</item>

or moving

android:textColorHint="@color/warm_grey"

from XML widget to EditTextBaseStyle

Try this:

 <style name="AppTheme.EditTextBaseStyle" parent="@android:style/TextAppearance">
    <item name="android:textColor">@android:color/darker_gray</item>
</style>

You can use the app:hintTextColor and the android:textColorHint attributes in your layout:

<com.google.android.material.textfield.TextInputLayout
    app:hintTextColor="@color/mycolor"
    android:textColorHint="@color/text_input_hint_selector"
    .../>

or you can define them in a custom style:

<style name="..." parent="Widget.MaterialComponents.TextInputLayout.FilledBox">
    <!-- The color of the label when it is collapsed and the text field is active -->
    <item name="hintTextColor">@color/my_color</item>

    <!-- The color of the label in all other text field states (such as resting and disabled) -->
    <item name="android:textColorHint">@color/my_selector_color</item>
</style>

The fix for me was to set the hint and the textColor on TextInputLayout, rather than on TextInputEditText as described here: https://material.io/develop/android/components/text-input-layout/

    <android.support.design.widget.TextInputLayout
        android:id="@+id/passwordTextInputLayout"
        android:hint="@string/add_nitrogen_template_name_label"
        android:textColorHint="@color/warm_grey">

        <android.support.design.widget.TextInputEditText
            android:textAppearance="@style/TextAppearance.Regular"
            android:textColor="@color/white"/>
    </android.support.design.widget.TextInputLayout>