You must complete Steps 1-7 of the Google Takeout method above. You need your subscriptions.json file on your computer.
You will use .
Some channels have custom names (e.g., /MrBeast ) instead of IDs ( /channel/UCX... ). You must prepend https://www.youtube.com/ to the custom URL. A good converter script (or Excel formula =CONCAT("https://www.youtube.com/", A2) ) will fix this. You must complete Steps 1-7 of the Google