Hi there.
I will show you how to create a working RSS feed reader URL for the YouTube channel.
1) Visit the channel you want to subscribe to. Let’s say this one:
https://www.youtube.com/channel/UCM1Bnpxipb8H4GJoITnJ0XQ
2) Now grab this:
https://www.youtube.com/feeds/videos.xml?channel_id=
and add the channel ID to the end of it after the =. Its the red part after the /channel/ in the channel URL :).
The entire link should look like this:
https://www.youtube.com/feeds/videos.xml?channel_id=UCM1Bnpxipb8H4GJoITnJ0XQ
Add the newly created URL to the RSS and watch the magic happen ;).
Cheers.
Andrzej