You can add the RSS feed of a youtube channel with the Tiny Tiny RSS bookmarklet, it's working for most channels, but not all for a reason I don't understand yet.
For example, "It's Okay To Be Smart" is at "www.youtube.com/user/itsokaytobesmart". Right click, view page source, search for "/channel/". That finds "<link rel="canonical" href="https://www.youtube.com/channel/UCH4BNI0-FOK2dMXoFtViWHw">". So the feed url is:
https://www.youtube.com/feeds/videos.xml?channel_id=UCH4BNI0-FOK2dMXoFtViWHw https://www.youtube.com/feeds/videos.xml?user=<username>
https://www.youtube.com/feeds/videos.xml?channel_id=<channel id>
https://www.youtube.com/feeds/videos.xml?playlist_id=<playlist id>
Would love to hear if there are more.