from pathlib import Path

root = Path(r"C:\Users\Admin\Desktop\AAPLICAZIONI\MIMMOECONSULENTI\AAAAAPPLICAZIONI NON TOCCARE QUI\GESTIONE_CLIENTI\DUPLICAZIONE\toilettatura\DASHBOARD\centraledash")
for p in root.rglob('*.php'):
    b = p.read_bytes()
    if b.startswith(b'\xef\xbb\xbf'):
        p.write_bytes(b[3:])