Set default values for ACF Textarea field in WP Admin

mods-acf-textarea.php

<?php

// No direct access
defined( 'ABSPATH' ) || exit;

/**
 * Set default values for ACF Textarea field in WP Admin
 */
add_filter( 'acf/validate_field', function( $field ) {

    if ( empty($field['type']) )
	return $field;

    if ( $field['type'] !== 'textarea' )
	return $field;
    
    // Set default values
    $field['rows']      = 2;
    $field['new_lines'] = 'br';
    
    /**
     * Other available options
     * 
     *     [ID] => 1
     *     [key] => field_681ad11eba380
     *     [label] => {Label will go here}
     *     [name] => {Field Name will go here}
     *     [aria-label] => 
     *     [prefix] => 
     *     [type] => textarea
     *     [value] => 
     *     [menu_order] => 2
     *     [instructions] => 
     *     [required] => 0
     *     [id] => 
     *     [class] => 
     *     [conditional_logic] => 0
     *     [parent] => 1
     *     [wrapper] => Array
     *        (
     *             [width] => 
     *             [class] => 
     *             [id] => 
     *         )
     *     [default_value] => 
     *     [maxlength] => 
     *     [allow_in_bindings] => 0
     *     [rows] => 2
     *     [placeholder] => 
     *     [new_lines] => br
     *     [_name] => 
     *     [_valid] => 1
     */

    return $field;
});