I'm with the grandparent here, but want to chime in that backups are also important. If all my files got encrypted, I'd only be out a couple of days time.
Smart ransomware will wait weeks or months before revealing itself. So you'll have been backing up a lot of encrypted documents, and your last clean backup may be quite old. It may be totally gone if you're rotating quickly.
But I essentially agree that Windows Defender is about as good as it gets. It's not perfect protection, but neither is any other product.
