import os
import xml.etree.ElementTree as ET
from mutagen import File
import numpy as np

def extract_rating(file_path):
    """
    Extracts the rating from the metadata 
    """
    audio = File(file_path)
    if 'rating' in audio:
        R = int(float(audio['rating'][0]))
        assert(0 <= R <= 5)
        return R
    return None

def calc_rating(rating):
    """
    foo_playcount stores the 0-5 rating as 'RatingFriendly' and a different
    integer as 'Rating', according to the equation below.
    Source: https://hydrogenaud.io/index.php/topic,85309.msg733606.html#msg733606
    """
    return int(np.round((63.75 + 42.5*(rating-1))))

   
def update_ratings(infile, outfile, folder_path):
    """
    Scans a folder recursively for audio files, extracts ratings and updates
    the XML data.
    """
    tree = ET.parse(infile)
    root = tree.getroot()
    for entry in root.findall('./Entry'):
        item = entry.find('Item')
        file_path = item.get('Path')
        if file_path:
            file_path = os.path.normpath(file_path)
            if any(file_path.lower().endswith(ext) for ext in ('.mp3', '.wav', '.flac', '.aac', '.mp4')):
                print('Scanning {}...'.format(file_path))
                rating = extract_rating(file_path)
                if rating is not None:
                    entry.set('Rating', str(calc_rating(rating)))
                    entry.set('RatingFriendly', str(rating))
    tree.write(outfile, encoding='utf-8', xml_declaration=False)

inxml = 'Library.xml'
outxml = 'Library_ratings.xml'
folder_to_scan = 'H:/MUSIC'

update_ratings(inxml, outxml, folder_to_scan)

Why not using Playlist viewer context menu | Playback Statistics | Import statistics from file tags? Or did I miss something?