in nutshell, you grab the user/channel_id, is always at browser URL when viewing user profile. Then you add the id taken to any of these URLs, examples

https://www.youtube.com/feeds/videos.xml?user=HALIDONMUSIC

https://www.youtube.com/feeds/videos.xml?channel_id=UCkfkd_x...

these are RSS, then you use an application RSS reader (aggregator) like https://github.com/martinrotter/rssguard/releases

or even online http://www.feedly.com/ https://www.inoreader.com