The first thing you want to do is download the 4K Video Downloader program using the link here:
https://www.4kdownload.com/products/product-videodownloader?r=free_license
Then once the program is open you copy past the url of the YouTube video you want to download and click the past link button in the program, then select if you want the MP4 or MKV video file. If you want the original 1080p or 4K file select the MKV version. Sometimes the original video is the MP4 file, but for some reason it changes from video to video basted on the frame rate used.
There are premium features to the service as well like channel subscriptions. You can subscribe to a YouTube channel in the program and set the program to automatically download video's as there uploaded in there original quality. (Keep in mind download 4K video uses a lot of bandwidth)
You can also turn on a feature called "Smart Mode" so you can save default settings and always have the video download in the same format. For example you can select that you want the original video file downloaded in MP4 or MKV, but like I said you can only download the original 4K video in MKV.
If you want subtitles for the video if they are there then you can go to the Preferences tab and select
"Embed subtitles in video if possible" box.
The only thing this program won't do is save the video thumnail of the video as the picture you see on the video after you download it, that would be a nice feature.
Have fun downloading.
