If you need to download videos safely, consider these options:

Using a "crack" or "serial key" from an unofficial source is dangerous for several reasons:

Offers a free tier or a one-time purchase license for premium features.

If you use the software frequently, upgrading to a legitimate license ensures you get lifetime updates on up to three computers without security risks. App Store - Apple

The free version is quite limited with noticeable ads; lacks built-in editing tools.

Cracked versions are unreliable and frequently stop working when the official software is updated.

You can use the official free version of 4K Video Downloader Plus, though it has daily download limits.