You want to have the very source of the video so that you can embed it on your own player and monetize it with pop ads, right? Since embedding the youtube player doesn't trigger the ads when users click play.
Well, the gdrive (and I guess instagram) method is uploading the videos directly on the platform, and finding the cdn url, to be fair I don't remember how to do it, since these urls are very well hidden behind a bunch of masks and other urls that are a generated string that constantly change, are valid only for a certain amount of minutes, and/or are bound to your ip (So if you open it from another IP, it won't work).
I used to do it with gdrive but that was in 2017 so I don't remember (I didn't want to pay for hosting because it would have been thousands in hosting fees a month, so I kept looking until I found this way to do it free. I guess that's your case as well)