YouTube has built in RSS, though they don’t advertise it anymore. The easiest way to get it is to go to a channel’s page, view the page source, and search “rssurl” (or alternatively search “xml” and go the the last time it shows up in the page). This should bring you to a link you can add to a feed reader of your choosing.
You can also use tools like browser extensions or NewPipe to get feeds in one click.