Looking to upskill in my free time and found some short-term courses offering certificates (and even recommendation letters)

Hey everyone!
I’m looking to upskill in my free time and found some short-term courses offering certificates (and even recommendation letters). Have any of you tried them? Are they worth it, or should I stick to free resources like YouTube or self-study? I’m especially interested in Data Analytics or Cybersecurity, but I’m open to other areas too.
Found Mayerfeld Consulting courses - Would love to hear your thoughts and experiences!