It may take some time depending on the number of files you have and the total size. You can use the "Email me when done" option to get notified once the archival completes. You can then download the created archive locally. Make sure to download it to your Google Drive shared folder or copy it there after download so it gets synced and backed up in the cloud.
You actually get the option to save your downloaded YouTube videos in different formats, which means they can be accessible in different ways and from different devices. There’s even the option to download to an MP3 file with most of these, which means that you can skip the video and be able to listen to the audio through your MP3 player or your phone. Each of these makes it easy for you to get the information without having to go through an internet connection in order to do it and easy to know how to download YouTube channel.
Since you're probably going to be paying for a backup service for years, cost is an important factor to consider. All the services rounded up here are subscription-based, but they partition their features and fees differently, so it's worth comparing plans closely before committing to one. Most construct pricing tiers based on the amount of cloud storage included, however, or by the number of devices you can use with an account. A few services offer permanent free accounts, but those plans impose paltry storage limits or restrict key features to the paid versions. Watch out for file-size upload limits as well.