To stay safe, users were advised to avoid interacting with pop-up ads or prompts to download additional "converter tools", use reliable ad-blockers to filter out malicious advertisements, and for software, download it only from the official developer's website rather than third-party app stores or file-hosting sites.
YouTube's official stance is that its content should be streamed, not downloaded. Its Terms of Service prohibit the downloading of any content without explicit permission from YouTube or the respective rights holders. For users who want an official, legal way to watch videos offline, is the only sanctioned method. This paid subscription allows for offline viewing within the YouTube app, albeit with some limitations. youtube video downloader 2021