backgroundTint...

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:tools="http://schemas.android.com/tools">
    <style name="AppTheme" parent="Theme.MaterialComponents.Light.NoActionBar">
    <item name="android:statusBarColor" tools:targetApi="l">@color/MoneyGreen</item> <!-- шторка уведомлений окрашивание -->
    <item name="materialButtonStyle">@style/Button.circle</item>

    </style>

    <style name="Button.circle" parent="Widget.MaterialComponents.Button">
        <item name="materialButtonStyle">@style/Button.circle</item>
        <item name="backgroundTint">@color/white</item>
        <item name="background">@drawable/circle</item>
        <item name="android:textColor">@android:color/black</item>
        <item name="fontFamily">@font/playfair_display</item>
    </style>

</resources>