It is possible to disable Google Fonts in Breakdance using the breakdance_register_font hook.

Example:

<?php

add_filter("breakdance_register_font", function ($font) {
    $isGoogleFont = !!$font['dependencies']['googleFonts'];

    if ($isGoogleFont) {
        return false;
    }

    return $font;
});

Please note that when using this hook, you will also want to remove Google Fonts from any Global Settings and elements. You can then add your own Custom Fonts.